Query by Image Content
Query by Image Content software allows you to search for images similar to one that you select. Consider trying out the free program Sepham SearchByDrawing, which is available for download here, http://www.sepham.com/. If you have a set of mostly images quite different images:
. . . and want to find which are similar to one that you're focused on, you load up your selected image on the left, check off a directory in the center, and get your results on the right.
The software does a tolerably good job of finding photos of other tigers, but as you can see it's more focused on the actual form of the object in the image. It finds the exact duplicate of our selected tiger, but it assigns a llama with a pose similar to the selected tiger a higher rank than the second photo of the tiger in the set. It doesn't find any similarity between the photo of the tiger and a drawing of one.