CamFind - CamFind is the very first mobile application that can photograph, identify, and provide information...
isk-daemon - isk-daemon is an open source database server capable of adding content-based (visual) image...
IQDB - Multi-service image search
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
PicsLikeThat - This is a visual and semantic image search system finding images on Fotolia.
Exif Metadata Image Search - Search image metadata on the Internet. Exif image metadata search engine