Viper
«GIFT: GNU Image Finding Tool»

Viper stands for Visual Information Processing for Enhanced Retrieval. This project is about Content-based Image Retrieval (CBIR) and, more generally Content-based Multimedia Retrieval. The emphasis in this project is set on giving the user full flexibility for formulating his/her needs. Relevance feedback is extensively used and a novel framework and architecture for fully exploiting the usage logs is defined. This is done in particular via the specification of MRML (Multimedia Retrieval Markup Language), an XML-based communication protocol. Our software is freely available as the GIFT (GNU Image-Finding Tool), distributed under the Gnutella Public Licence.
For processing your queries the program relies entirely on the content of the images, freeing you from the need to annotate all images before querying the collection. The GIFT comes with a tool which lets you index whole directory trees containing images in one go. You then can use the GIFT server and its client, to browse your own image collections.
(Source: Viper Homepage)