Search for images based on color distribution and shape, very fast searching once the images are loaded. Image recognition based on color histograms.
Ability to store loaded data as xml so you don't have to reload the images each time.
Written in c#, source code runs in VS 2008 Express or SharpDevelop
Here is a screenshot of a list of search results showing the result score and a thumbnail of the image, the image at the top with a 0 score is the image being searched for: