MobShare: Controlled and Immediate
`Sharing of Mobile Images
`Risto Sarvas1, Mikko Viikari2, Juha Pesonen2, and Hanno Nevanlinna2
`
`
`1Helsinki Institute for Information Technology (HIIT)
`P.O.Box 9800, 02015 HUT, Finland
`risto.sarvas@hiit.fi
`
`
`2Futurice
`Merimiehenkatu 29, 00150 Helsinki, Finland
`{mikko.viikari, juha.pesonen,
`hanno.nevanlinna}@futurice.fi
`
`ABSTRACT
`In this paper we describe the design and implementation of a
`mobile phone picture sharing system MobShare that enables
`immediate, controlled, and organized sharing of mobile pictures,
`and the browsing, combining, and discussion of the shared
`pictures. The design combines research on photography, personal
`image management, mobile phone camera use, mobile picture
`publishing, and an interview study we conducted on mobile phone
`camera users. The system is based on a client-server architecture
`and uses current mobile phone and web technology. The
`implementation describes novel solutions in immediate sharing of
`mobile images to an organized web album, and in providing full
`control over with whom the images are shared. Also, we describe
`new ways of promoting discussion in sharing images and enabling
`the combination and comparison of personal and shared pictures.
`The system proves
`that
`the designed solutions can be
`implemented with current
`technology and provides novel
`approaches to general issues in sharing digital images.
`
`Categories and Subject Descriptors
`H.5.1 [Information interfaces and presentation (e.g., HCI)]:
`[Information
`systems applications]:
`Multimedia; H.4.3
`Communications Applications.
`
`General Terms
`Design, Human Factors
`
`Keywords
`Image Management, Wireless
`Camera Phones, Digital
`Multimedia Applications, Multimedia Tools.
`
`1. INTRODUCTION
`People share their digital pictures by email, web publishing, paper
`prints, slideshows, and often simply by showing from the
`camera’s LCD screen. Several current consumer products take
`into account sharing, managing, and archiving of personal media.
`Software like ACDSee [1], Adobe Photoshop Album [2], or
`Permission to make digital or hard copies of all or part of this work for
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`MM’04, October 10–16, 2004, New York, New York, USA.
`Copyright 2004 ACM 1-58113-893-8/04/0010...$5.00.
`
`
`Apple iPhoto [3] facilitate searching, browsing, and archiving of
`pictures, and sharing them with other people. Also, there has been
`significant academic research done on personal photo collection
`management, where the focus has been on automatic organization
`of image collections [7, 12, 14, 24], and innovative user interface
`designs for browsing and searching the collection [5, 11, 13, 19].
`Mobile phones with a built-in digital camera are at the moment
`outselling digital cameras [20] and therefore challenging digital
`cameras’ position as the number one consumer media-recording
`device. However,
`the dominant consumer and
`research
`applications mentioned above take little into account the special
`characteristics of mobile phone cameras, mainly, that mobile
`phone cameras are primarily a communication device.
`New picture publishing and sharing systems are emerging which
`take advantage of the special characteristics of camera phones [6,
`10, 22, 23, 25, 29, 32]. In contrast to regular digital cameras,
`camera phones’ technical characteristics include several network
`connections that enable sharing images directly from the phone
`(e.g., GSM/GPRS, Bluetooth, and infrared), computing resources
`accessible by standardized programming interfaces (e.g., J2ME,
`BREW, and Symbian), and access to contextual and social
`information on the phone (e.g., calendar, location data, time and
`date, address book, as well as call and messaging logs). Camera
`phones also have the ubiquitous characteristics of mobile phones
`in general: people carry them everywhere and they become an
`indispensable accessory in people’s lives.
`In this paper we present a mobile picture sharing system
`MobShare that focuses on immediate and controlled sharing of
`pictures within a circle of acquaintances. Our system design is
`based on related literature and an interview study we conducted
`on mobile camera phone users. The main contributions of
`MobShare to mobile picture sharing are the following:
`Immediately sharing captured mobile images from the
`phone to an organized and manageable web album.
`Providing full control over whom the images are shared
`with by leveraging the social contact information stored
`on the phone’s address book.
`Integrating discussion into the sharing and viewing of
`mobile images.
`Enabling the combination and comparison of pictures
`both taken by the user and shared by other users.
`In the following subsections we discuss related work, our research
`methodology, and present primary use cases for MobShare.
`Section 2 discusses the novel solutions implemented in sharing
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`Canon Exhibit 1031, Page 1
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`the novel solutions
`mobile pictures. Section 3 discusses
`implemented in browsing, combining, and discussing the shared
`mobile pictures. Section 4 gives a system architecture overview,
`Section 5 presents an evaluation of the system, Section 6
`discusses future research, and Section 7 concludes.
`1.1 Related Work
`The design of MobShare was based on related work and literature
`on
`traditional and digital photography, personal
`image
`management, and mobile camera phone use as well as on analysis
`of existing mobile imaging systems.
`1.1.1 Related Literature
`Research in cultural studies has studied what people photograph
`and for what purposes (see e.g., [15, 30]). Studies by [4, 31] have
`looked into what purposes do photographs and other memorabilia
`serve in people’s lives, and [9, 26] have studied how people
`manage and share their digital pictures.
`The problem of managing the rapidly growing personal image
`collections has been researched from the user interface point of
`view, focusing on the organization, browsing and searching of
`pictures (see e.g., [5, 11, 13, 19]). Also, the event-based automatic
`categorization of images based on their timestamp metadata has
`been studied (see e.g., [7, 12, 14, 24]), as well as location
`information in images [33].
`However, personal image management and people’s picture
`sharing habits in the domain of mobile pictures has not been as
`widely studied as in the general digital imaging domain. Currently
`picture taking and sharing using mobile phones has been studied
`in [16, 17, 18, 21]. Our previous research in [8, 27, 34] has looked
`into image annotation and automatic metadata generation on
`mobile phones.
`1.1.2 Related Systems
`Related systems [25, 29, 32] enable mobile picture publishing on
`the Internet (i.e., “photo blogging” or “moblogging”) but take
`personal image management issues little into account. They focus
`on publishing images immediately from the phone to the Internet
`and having discussion functionality. The main difference to
`MobShare is that in these “blogging” systems controlling the
`sharing of images and combination of shared images is not
`supported, also, picture organization features are limited.
`Other related systems [6, 10, 23] have more specific features for
`personal image management, for example, editing, organizing into
`folders, and choosing images for publishing. Also, these systems
`enable sharing of pictures to specific people. The contribution of
`MobShare into these systems is enabling the sharing directly from
`the phone itself and using the phone’s address book in the
`process. In addition, the shared picture folders can be easily
`combined and compared as described later.
`Lifeblog [22] combines the media and messages on the phone into
`a media diary on a PC. Like MobShare, Lifeblog takes advantage
`of the time and date information in organizing and visualizing the
`pictures on a timeline. However, unlike in MobShare, there is no
`sharing or publishing feature.
`1.2 Methodology
`Based on related work we conducted an interview study. Ten
`mobile phone camera users in the Helsinki area were interviewed
`about their use of film, digital, and mobile phone cameras and
`
`pictures. The interviewed were men and women age 19 to 32 who
`had had their camera phones for at least two months. Each
`interview covered picture-taking habits and situations, picture
`sharing, and going through the interviewee’s pictures.
`The results from the literature and interview studies showed that
`sharing of mobile pictures has the same motives and uses as
`traditional sharing and discussion of pictures (e.g., telling about
`travels, reminiscent of shared events), in addition to new ways
`and uses enabled by the technology (e.g., documenting everyday
`life, improvised pictures). However, current mobile picture
`sharing applications support only partly the whole mobile photo
`capture and sharing process: some support controlled sharing,
`some support web publishing, and some support discussion. From
`these results we designed and implemented our prototype system
`MobShare. The objective of the system was to wholly support the
`mobile picture taking, sharing, and discussion process. Especially,
`the goal was to learn how the issues and requirements identified
`from the studies could be implemented with current and widely
`adopted technology. The technology is discussed in more detail in
`Section 4.
`1.3 Primary Use Cases
`We present two use cases to give an overview of the system. The
`first use case describes the setting for Section 2: capturing and
`sharing of images to the remote server using the client
`application. The second use case describes the setting for Section
`3: viewing the user’s own images and the images shared by other
`people using the desktop web browser component.
`1.3.1 Capturing & Sharing Using the Client
`The user captures a picture using a camera program integrated to
`the MobShare client. After taking a picture the user selects the
`new image or any set of images on the phone to be posted. By
`posting we mean the user experience of uploading the images to
`the remote server on the Internet (see Figure 1 for screenshots).
`After selecting the images to be posted, the user chooses a folder
`where the images will be located. The folder can be an existing
`folder he has created before, or he can create a new folder. If he
`creates a new folder, he names the folder and selects the people
`
`Figure 1. The posting process where a) the images are
`selected, b) posting initiated, c) new folder created, d)
`named, e) the people selected, and f) finally the images
`are uploaded.
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`who he wants to share the folder with. The sharing procedure is
`similar to sending a text message or making a phone call: he
`selects the people he wants to share the images with from the
`phone’s address book. The phone transfers the pictures to the
`remote MobShare server over the phone network.
`If the people the user shared the images with have not used
`MobShare before they will receive an SMS notification including
`a password and instructions for viewing the images. Old users
`also have the option to receive SMS notifications of new shared
`pictures.
`
`
`
`Figure 2. The Horizontal Timeline View of the user’s
`(Chris) own folders and folders shared by others
`(Markus and Anna). The two selected folders are in
`darker color.
`1.3.2 Viewing Images Using the Desktop Component
`After logging into the system the user is presented with his own
`page of images. On the top of the page on a horizontal timeline
`are his own folders of images and the folders that others have
`shared with him (see Figure 2). For each folder the user can see if
`there are new pictures that he has not viewed yet.
`The user can select one or several of the folders (see Figure 2,
`where Chris has selected two folders: his own “Conference Trip”
`folder and Markus’s “San Jose 2004”). The selected folders can
`be viewed as a gallery of thumbnails (see Figure 3). The gallery
`view shows the thumbnails one after another in temporal order as
`one large collection. The selected folders can also be viewed on a
`vertical timeline of thumbnails (see Figure 4). The timeline view
`shows the thumbnails on synchronized vertical timelines. Both the
`gallery view and the timeline view also show who else can see the
`selected folders (e.g., Markus and Anna for Chris’s folder
`“Conference Trip”). If the folder is the user’s own, then the user
`interface shows who has already visited (i.e., viewed) the folder.
`The user can also modify the viewing rights of his own folders.
`On the right side of the gallery view is a conversation board that
`shows small thumbnails of the pictures that have been commented
`on and the respective comments (see Figure 3). The user can click
`on any thumbnail to open a pop-up window. The small window
`contains the picture in its full size, together with the capture time
`and date information, description of the image, and a possibility
`to discuss the image. If the image is user’s own, he can also edit
`the description, rotate or delete the image, and delete comments.
`2. IMMEDIATE SHARING & CONTROL
`Sharing pictures with other people is probably the most popular
`activity with photographs. Paper photos are shared with relatives
`and friends by showing them personally, or including photos in
`letters [9]. Digital pictures are often shared by email, burned on a
`CD, published on a web page, or shared from a computer,
`television, or camera screen [4, 9]. In addition, people often print
`digital pictures and share them like traditional paper photos.
`
`Pictures taken on a mobile phone camera can be shared in the
`same ways as any digital pictures, but the inherent network
`connectivity supports sharing the images immediately after
`capture. For example, using MMS (Multimedia Messaging
`Service), pictures can be sent directly from one phone to other
`phones and email addresses. Images can also be sent to a web
`service, which publishes the images on a web page. As mentioned
`before, this kind of web publishing of images from a mobile
`phone is often called photo blogging, or moblogging.
`Compared to traditional sharing of digital images, sharing images
`directly from the phone has one step less for the user to go
`through: with camera phones there is no need to transfer the
`images to a networked PC to be able to share them. Mobile phone
`images can be shared immediately after capture from the actual
`capture device, and the images can be shared over the network to
`distant locations. This kind of combination of immediacy and
`remote sharing has not been possible with film or traditional
`digital cameras.
`As mentioned previously, current mobile image “blogging” and
`photo gallery software (see, e.g., [6, 10, 23, 25, 29, 32]) enable
`immediate sharing of images on a webpage. After capturing, the
`images are sent one at a time to a specific address. Another way
`of sharing images from the phone is the standardized MMS
`messaging, which enables direct sharing of multimedia to email
`addresses and MMS compatible phones. Nevertheless, these
`software take very little account of the organization and handling
`of images, which are the key features in personal image
`management applications. Also, the mobile image “blogging”
`
`Figure 3. Gallery view and discussions. The folder-level
`discussion is on the left above the gallery view. The
`visibility and visitor information of each folder. The
`summary of picture-level discussions are on the right.
`
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`In the MobShare system we take advantage of the users’
`motivation to share images to make the organization work less
`tedious and more rewarding. As the user shares the images, the
`client program’s user interface requires him to categorize the
`shared images into a new folder or an existing folder. Our
`previous work in [34] has shown that people are not motivated to
`thoroughly annotate their pictures, especially on a mobile phone.
`Combining the time and date metadata in the pictures with the
`user-managed categorization into folders we were able to
`visualize the folders of images on a simple calendar view (i.e., the
`horizontal timeline view of image galleries in Figure 2). The
`benefits of these organized galleries are discussed later in Section
`3 where we describe the image browsing implemented in
`MobShare.
`2.2 Controlled Sharing
`One of the concerns about sharing images online is the question
`of privacy, that is, who has access to the images. When paper
`photos are shared restricting access is easy, as well as with digital
`photographs as long as they are not published on a public
`webpage in the Internet.
`According to our interviews people share pictures almost solely
`with their circle of acquaintances (i.e., intimates like family and
`close friends). The interviewed also told that within this circle of
`five to fifteen known people privacy issues are not a major
`concern and they feel more comfortable sharing pictures inside
`this group. One of the interviewed explained some of his pictures:
`“These images were taken while everyone was drunk. No one
`would like to put these kind of images into the web.” Another
`interviewed had even gone through the task of creating a group
`website on Microsoft MSN1 to share images with his friends and
`control the images’ visibility. Camera phone studies [16, 17] also
`support the users’ requirement to be able to control the visibility
`of shared images.
`Controlling who can see shared digital pictures is often done by
`sending the pictures as email attachments. In email the user has
`control over who the recipients are, and the recipient can often see
`who else has received the message and attached pictures. Another
`popular way of limiting the viewing of digital images is to have
`web page that is either password protected or unlinked. However,
`search engines can find unlinked pages.
`Mobile phones enable a novel way of controlling image sharing.
`The phone’s address book contains all the names and phone
`numbers of the user’s circle of acquaintances. In the MobShare
`system, we take advantage of this information: the user can select
`from the phone’s address book the people with whom he wants to
`share the images. Using the address book for defining viewing
`rights provides the user with an intuitive list of his acquaintances,
`and
`it provides
`the system with relatively unique user
`identification numbers (i.e., each person’s phone number, that is,
`the MSISDN). Also, as mentioned previously, the same address
`book user interface is familiar to the user from making phone
`calls, emailing, and text and multimedia messaging.
`Using phone numbers for user identification has clear benefits.
`There is no need to create any system specific identifiers for
`users, phone numbers are more accurate identifiers than names
`
`
`1 http://groups.msn.com/
`
`Figure 4. Vertical timeline view of pictures. Here are
`the same two selected folders as in Figure 4, but on
`separate timelines according to the owner of the folder.
`software are designed for publishing images on the Internet, and
`hardly take into account the need for privacy and control over
`who can view the images.
`In the following subsections we discuss how we implemented the
`organization of shared and received images, enabled full control
`over who the images are shared with, and the benefits of
`implementing this on a dedicated client-side program.
`2.1 Organizing Shared and Received Images
`Due to the always-present nature of mobile phones, people have
`the opportunity to take images at any moment, and send them
`immediately to other people. This will increase the number of
`images people capture, send, and receive, which makes the need
`to organize the images more acute.
`Organizing and managing large collections of images is difficult
`on the mobile phone itself because of its small screen size and
`limited input keypad. To tackle this problem images are often
`simply deleted or uploaded to a computer where they are stored
`on the operating system’s folder hierarchy, or they are organized,
`managed, edited, and shared using specialized image management
`software.
`However, images received from other people are often not
`managed at all. Before they can be managed or even browsed
`efficiently, the received images have to be moved or saved from
`the email or MMS inbox, CD, or web page. In practice, they often
`remain in the inbox or web page without any organization, and
`are hardly ever managed with the same image management
`application as the user’s own images.
`Another problem in organizing images is the lack of user
`motivation in going through images and annotating them with
`metadata or keywords. Even simple moving of images into folders
`with informative names can be tedious work. Therefore, the work
`is often postponed into the future, thus both forgetting information
`about the pictures (e.g., where it was taken, who are the people in
`the picture) and eventually creating a monumental task of
`organizing old pictures [9].
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`that vary (e.g., the same person can be called by his first name,
`surname, or nickname), and phone numbers are easily available
`because the salient people, with whom images are most often
`shared, are in the user’s phone's address book.
`The disadvantages of phone numbers are that one person may
`have several phone numbers or people’s phone numbers may
`change. The latter issue is taken into account by allowing users to
`change their phone numbers in the system. The issue of several
`phone numbers has to be tested in user test to understand better
`the practical implications.
`2.3 Dedicated Client Application
`Several of the people we interviewed mentioned the ease of
`taking pictures with their camera phone. The effort of taking a
`picture was considered low, because the camera was ready for
`use, always available and reachable. One of the interviewed
`commented: "[The camera phone] is always with you, and ... it’s
`so small and you can take it to any place, and you take pictures
`wherever you happen to be." However, the easiness ended when
`people wanted to share the pictures. One of the problems was that
`not everyone within the users' circle of acquaintances had a phone
`capable of receiving images, or the phone was not correctly
`configured.
`In the MobShare system we implemented image capture and
`sharing in the same client program. This way the user had one
`contiguous process from taking the picture to sharing it, and we
`were able to control the usability and visual image of the user
`interface for the whole process. Also, having both capture and
`sharing under one application enabled more control over the
`gathering of contextual metadata at the time of capture. For
`example, currently for every image we store on the server capture
`time, date, and GSM network cellID information (the cellID can
`be used to infer location, however, it is not used in the current
`version of MobShare). A dedicated client application can also
`access other information on the phone, for example, the user’s
`calendar events or call and message logs. This information can be
`used to infer more descriptive metadata about the context of
`image capture (e.g., who, where, when) [8, 27, 34].
`3. BROWSING, COMBINING, AND
`DISCUSSING
`Browsing, combining, and discussing the pictures is more
`convenient using a desktop computer with a large screen, a
`mouse, and a keyboard rather than using a mobile phone with a
`small screen and a limited input keypad. Therefore, browsing,
`combining, and discussing was designed and implemented for a
`web browser that connects to the web server where the posted
`images are located.
`As mentioned in Sections 2, the images on the server are
`categorized into folders as they are shared from the phone, and
`therefore, the recipients of the shared image galleries have an
`organized view of the images. In this section we present and
`discuss how the picture collections were visualized in the system,
`how we enabled combination and comparison of shared galleries,
`and how discussion about the images was promoted.
`3.1 Visualization of Pictures
`People value simple browsing capabilities in going through digital
`pictures more than highly advanced techniques like audio
`annotation or image-based queries [26]. Therefore, our focus on
`
`the implementation of the picture visualization was to keep it
`simple, and to have shared images organized also from the
`recipients’ point of view.
`3.1.1 Horizontal Timeline of Folders
`The visualization and browsing of pictures in MobShare is based
`on a horizontal timeline of folders. Both the user’s own folders
`and the folders shared with him are displayed on the same
`timeline. The user creates the folders either using the mobile
`phone (see Figure 1) or the web browser. The position and the
`width of the folder on the timeline reflect the capture dates of the
`photos in that folder (see Figure 2). This approach combines the
`familiar folder metaphor with an intuitive calendar timeline. Also,
`it is easily implemented because the required time and date
`metadata is practically always available in mobile pictures. From
`the horizontal timeline the user can select one or several folders to
`be presented as galleries of thumbnails.
`3.1.2 Gallery View and Vertical Timeline View
`Once the user has chosen the folders to view from the horizontal
`timeline, he can view the images either as a gallery of thumbnails
`in chronological order (see Figure 3), or as a set of vertical
`timelines (see Figure 4). In the gallery view all the images from
`the selected folders are displayed in a chronological order
`regardless of whose images they are. The user can click on a
`thumbnail to open a pop-up window where the image is shown in
`its actual size, and he can discuss the image. In the vertical
`timeline view the thumbnails of each selected gallery are on
`separate vertical timelines side by side. The view can be scrolled
`if not all the thumbnails fit the screen. Like in the gallery view,
`the thumbnails can be clicked to see the full size image and
`discuss it.
`3.1.3 Notification of New Pictures
`As we discussed in Section 2, mobile images can be shared
`immediately after capture. For example, a user traveling abroad
`can post images for others to see as the trip progresses. To support
`this kind of immediacy we implemented a visual notifier in the
`picture folders to show if there are new pictures (see Figure 2).
`Similarly to email programs, as the user logs into MobShare he
`can quickly see by the color of the picture markers if someone has
`posted new pictures for him to see, and in which folder.
`If the user with whom the pictures are shared is not a user of
`MobShare, he gets an SMS notification which includes a
`password and instructions for becoming a user. All users also
`have the option to get SMS or email notifications when new
`pictures are shared with them.
`3.2 Combining and Comparing Pictures
`In browsing pictures, the user can combine his own images and
`other people’s images into one collection. As emphasized
`previously, MobShare is designed for people who know each
`other in advance (i.e., close friends, relatives, or colleagues).
`Therefore, it can be assumed that these groups occasionally attend
`the same events and are often the subject of each other’s pictures.
`For that reason one of the main functionalities of the MobShare
`system is the possibility to combine and compare different
`people’s picture folders.
`For example, in the screenshots in Figures 1 through 4, two
`friends (Chris and Markus) who attend the same conference take
`pictures with their mobile phone cameras and share them with
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`each other and their mutual friend (Anna). Using the browser
`component of MobShare, any one of the three can select the two
`friends’ folders of the conference trip and view them as one
`gallery (as in Figure 3). This kind of sharing enables people to
`collaboratively document an event with several cameras and
`easily combine the pictures into one gallery.
`On the other hand, using the vertical timeline view the user can
`distinguish between the selected folders and compare the pictures
`on the same timeline. For example, Anna who did not attend the
`conference wants to compare Chris’s and Markus’s individual
`recordings side by side (see Figure 4).
`Combining and comparing folders is intuitive when the pictures
`viewed are based on an event. However, combination and
`comparison of non-event pictures can also be meaningful for the
`user. For example, combining two users’ folders of everyday life
`can be entertaining, or comparing folders of pet animal pictures.
`As discussed in Section 2, having the user organize his pictures
`for sharing (i.e., categorizing the pictures into folders) removes
`the tedious work of organizing the pictures later on. And by
`sharing the pictures in organized folders the recipients of those
`pictures can (re)use the same organization. Without this kind of
`sharing and organization, combining and comparing one’s own
`images to the images received from other people would require a
`lot of effort.
`3.3 Discussing Images
`People take pictures to discuss them. Whether it be to tell about a
`vacation trip, to reminisce a shared experience, or to joke about a
`comic image [4, 9, 18]. Discussion about pictures is present in
`sharing images with email, showing paper photos, writing
`captions, and image MMS messaging. Often pictures are taken
`only to initiate conversation or contact [16]. In other words,
`discussion or communication in one form or another is an integral
`part of sharing images, perhaps even the primary reason [18].
`In the MobShare system we integrated discussion functionality
`into picture browsing, and promoted it by making the possibility
`to discuss visible all the time. Having the discussions in the server
`database also stores and archives the discussions along with the
`pictures. Therefore, the discussions are not lost like they easily
`are in MMS or email messaging.
`3.3.1 Presenting Several Discussion Threads
`Discussion about pictures can be about individual images or the
`whole image folder (e.g., discussion about a picture of the Eiffel
`Tower or discussion about a whole trip to Paris). In the MobShare
`system the discussion about individual pictures is implemented in
`the pop-up window where the image is shown in full size. The
`folder-level discussion is implemented in the gallery view.
`However, having a discussion for each individual image results in
`several discussion threads. To make the viewing of these several
`discussion
`threads easier, each picture-level discussion
`is
`summarized on the gallery-level (see Figure 3). This enables the
`user to quickly skim through the latest discussions on picture-
`level without opening each image. By clicking the small
`thumbnail image next to the discussion in the summary, the
`picture pop-up window is opened, and the user can discuss the
`image. In other words, the pictures can be viewed also by the
`discussions they have.
`
`3.3.2 Seeing Who Can Read the Comments
`An issue in discussing images is to know who else can see the
`conversation and take part in it. For example, when images are
`shared in email attachments the recipients of the email can usually
`see who else has received the images, and reply to the email
`accordingly.
`In the MobShare system the users see who else can view the
`selected folders. In other words, the list of people selected by the
`user from his phonebook is visible to the people in the list (see
`Figure 3 and 4). Therefore, each user is aware of the people who
`can read the discussions. Also, the people whom the folder is
`shared with probably know each other, and showing the names of
`these people creates a feeling of togetherness and familiarity.
`
`4. SYSTEM OVERVIEW
`The MobShare system consists of a mobile phone client
`application and a web application server that is accessed using a
`regular web browser. Sharing pictures from phone to phone
`requires special phones, which are less common than web access,
`and importantly, accessing pictures using a web browser enables
`d