Entipic.com is a service offering every subject/topic (i.e., Google, Barack Obama, Paris, etc.) a representative image that can be freely used by any application.
The idea of the service is quite simple and can be easily understood by taking as an example the service provided by Gravatar.com So, Gravatar.com offers to every email a picture/avatar, while Entipic.com provides a picture to each subject/topic.
The Entipic service can be especially used by news websites/blogs in order to associate a representative image to each tag/topic in the news.
To associate an image to a news topic on your site you must complete the following address:
http://cdn.entipic.com/en/barack-obama.jpg- is associating a 50x50 pixel image to Barack Obama (English) topic.
http://cdn.entipic.com/en/c/twitter.jpg- is associating a 150x150 pixel image to Twitter topic.
http://cdn.entipic.com/fr/b/paris.jpg- is associating a 100x100 pixel image to Paris (Franch) topic.
http://cdn.entipic.com/ro-ro/b/Adrian_Ursu.jpg- is associating a 100x100 pixel image to Adrian Ursu (Romania in Romanian language) topic.
For each request the system will return an image associated with the news topic. If the topic is unknown (or new) for the system, it will return a temporary image (1x1 pixel). Meanwhile, the system will search for the best picture to be associated with the news topic and for the next requests the system will return the found picture.
Entipic respects the copyright of the pictures used by the system. The source of the image is included. The most of the images are taken from Wikipedia.