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Photo sharing is the publishing or transfer of a user's digital photos online, thus enabling the user to share them with others (publicly or privately). This function is provided through both websites and applications that facilitate the upload and display of images. The term can also be loosely applied to the use of online photo galleries that are set up and managed by individual users, including photoblogs. Sharing means that other users can view but not necessarily download the photos, users being able to select different copyright options.
The first photo sharing sites originated during the mid to late 1990s primarily from services providing online ordering of prints (photo finishing), but many more came into being during the early 2000s with the goal of providing permanent and centralized access to a user's photos, and in some cases video clips too. Webshots, SmugMug, Yahoo! Photos and Flickr were among the first. This has resulted in different approaches to revenue generation and functionality among providers.
While photoblogs tend only to display a chronological view of user-selected medium-sized photos, most photo sharing sites provide multiple views (such as thumbnails and slideshows), the ability to classify photos into albums, as well as add annotations (such as captions or tags) and comments. Some photo sharing sites, even small ones with only a few million photos, provide complete online organization tools equivalent to desktop photo management applications.
Desktop photo management applications may include their own photo-sharing features or integration with sites for uploading images to them. There are also desktop applications whose sole function is sharing photos, generally using peer-to-peer networking. Basic photo sharing functionality can be found in applications that allow you to email photos, for example by dragging and dropping them into pre-designed templates.
Photo sharing is not confined to the web and personal computers, but is also possible from portable devices such as camera phones, using applications like Streamzoo that can automatically transfer photos as you take them, to photo sharing sites and photoblogs, either directly or via MMS. Some cameras now come equipped with wireless networking and similar sharing functionality themselves.
Revenue models 
Photo sharing sites can be broadly broken up into two groups: sites that offer photo sharing for free and sites that charge consumers directly to host and share photos.
Of the sites that offer free photo sharing, most can be broken up into advertising-supported media plays and online photo finishing sites, where photo sharing is a vehicle to sell prints or other merchandise.
Paid sites typically offer subscription-based services directly to consumers and dispense with advertisements and sometimes the sale of other goods.
These designations are not hard and fast and some subscription sites have a limited free version. Consumers can share their photos directly from their home computers over high speed connections through peer-to-peer photo sharing using applications. Peer-to-peer photo sharing often carries a small one-time cost for the software. Some sites allow you to post your pictures online and they will then project the image onto famous buildings during special events, while other sites let you insert photos into digital postcards, slide shows and photo albums and send them to others.
Some free sites are owned by camera manufacturers, and only accept photos made with their hardware.
Subscription-based photo sharing 
In return for a fee, subscription-based photo sharing sites offer their services without the distraction of advertisements or promotions for prints and gifts. They may also have other enhancements over free services, such as guarantees regarding the online availability of photos, more storage space, the ability for non-account holders to download full-size, original versions of photos, and tools for backing up photos. Some offer user photographs for sale, splitting the proceeds with the photographer, while others may use a disclaimer to reserve the right to use or sell the photos without giving the photographer royalties or notice.
From the turn of the 21st century, some sites began integrating video sharing as well.
Peer-to-peer photo sharing 
With the introduction of high speed (broadband) connections directly to homes, it is feasible to share pictures and movies without going through a central service. The advantages of peer-to-peer sharing are reduced hosting costs and no loss of control to a central service. The downsides are that the consumer does not get the benefit of off-site backup; consumer Internet Service Providers (ISPs) often prohibit the serving of content both by contract and through the implementation of network filtering, and there are few quality guarantees for recipients. However, there are typically no direct consumer costs beyond the purchase of the initial software, provided the consumer already has a computer with the photos at home on a high speed connection. Applications like Tonido photos provide peer-to-peer photo sharing.
Peer-to-server photo sharing 
Operating peer-to-peer solutions without a central server can create problems as some users do not leave their computers online and connected all the time. Using an always-on server like Windows Home Server which acts as an intermediate point, it is possible to share photos peer-to-peer with the reliability and security of a central server. Photos are securely stored behind a firewall on the Windows Home Server and can be accessed only by those with appropriate permissions.
Peer-to-browser photo sharing 
A variation on the peer-to-peer model is peer-to-browser, whereby images are shared on one PC with the use of a local (on the host computer) software service (much like peer-to-peer) but made available to the viewer through a standard web browser. Technically speaking, this may still be described as peer-to-peer (with the second peer being a web browser) but it is characteristically different as it assumes no need to download peer software for the viewer. Photos are accessed by regular URLs that standard web browsers understand natively without any further software required. Consequently, photos shared in this way are accessible not only to users who have downloaded the correct peer software (compatible with the software in use by the sharer).
Peer-to-browser sharing has (similar to peer-to-peer) reduced hosting costs, no loss of control to a central service, and no waiting for files to upload to the central service. Furthermore, universal web browser access to shared files makes them more widely accessible and available for use in different ways, such as embedding in, or linking to, from within web pages. As with peer-to-peer, the downsides are lack of off-site backup, possible inhibition by some ISPs, and limitations in speed of serving.
Social Network Photo Sharing 
Sharing photos through social networks has become increasingly popular as well. Facebook application and online photo aggregator Pixable expects that Facebook will have 100 billion photos by Summer 2011. Social Network photo sharing allows users to share photos with only those they specify as being allowed to see those albums, whether it is all users, or only those whom they are connected with.
Mobile photo sharing 
Photo sharing via mobile phones has become the rage of 2011. Several networks and applications have sprung up offering capabilities to share photos directly from mobile phones to social networks. The most prominent of these is Instagram which has quickly become the dominant mobile social network with over 200 million members. Other applications and networks offering similar service and growing in popularity include Streamzoo, Path, and Starmatic.
Web photo album generators 
Software can be found on the internet to generate your own photo albums, usually to share photos on the web, using a home web server. In general, this is for advanced users that want to have better control over the look and feel of their web albums and the actual servers they are going to run on.
Privacy and security 
Online theft and photo fraud have become major issues in the photo sharing market. The US Ad Council recently created an advertising campaign to warn users of the dangers of posting personal photos to public websites.
Photos classification 
Photo sharing sites usually propose several ways to classify images. Most sites propose at least a taxonomy where images can be grouped within a directory-like structure in so-called "galleries". Some sites also allow users to classify images using tags to build a folksonomy. Depending on the restrictions on the set of users allowed to tag a single document and the set of tags available to describe the document, one speaks about narrow and broad folksonomies. A folksonomy is broad when there is no restriction on the set of taggers and available tags. When there are limitations, the folksonomy is called narrow. Another mechanism is coupling taxonomy and folksonomy, where tags associated to galleries and artists are cascaded to the galleries and artist's pictures. Broad taxonomies have interesting properties like the power law.
Photo Tagging 
Photo Tagging is the process that allows users to tag and group photos of an individual or individuals. With facial recognition software tagging photos can become quicker and easier; the more tagging done of an individual the more accurate the software can be. Photo tagging is a way of labeling photos so that viewers can know who is who in the picture. On most online photo sharing sites such as Facebook, a tag can also be used as a link that when clicked will take you to the person's profile that was tagged. Most of the time photos can only be tagged by the user to uploads the photo but on some sites photos can be tagged by other users as well. These tags can be searched for across the entire internet or in private data bases.
Geotagging a photo is the process in which a photo is marked with the geographical identification of the place it was taken. Most technology with photo taking capabilities are equipped with GPS system sensors that routinely geotag photos and videos. see Geotagging
Online photo sharing websites 
- BeFunky Photo Editor
- Mobile Me
- Wikimedia Commons
- Windows Live Photos
See also 
- Comparison of photo gallery software
- Digital photo frame
- File sharing
- Image hosting service
- Online file storage
- List of photo sharing websites
- advertising campaign
- Brown, F. (2007). "Metadata Goes Mainstream—about online photo galleries and the lessons we can learn."
- Vanderwal, T. (2005). "Explaining and Showing Broad and Narrow Folksonomies."
- Pietro Speroni (2005). "On Tag Clouds, Metric, Tag Sets and Power Laws."