Flickr, the popular photo sharing site has an open API that allowed developers to build applications on top of Flickr. Some of the featured applications are earlier included in Flickr API Services page as a list. Now Flickr has created an application showcase called App Garden.
The app garden shows the list of application built for various Flickr functions like uploading, retrieving photos. You can explore the apps using the tags or search for apps using the search box. Each app has its own page where users can comment and add them to their favorites.
Now you can find out which application your friends are using for uploading the photos. Each photo pages shows Uploaded using “appname”, this is available only of the application is added to the app garden.