PickStackr - Organize and manage your camera roll
Yandex.Images - search for images on the internet, search by image
SlickPix - Instantly create dynamic events from multiple cameras
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
Carousel - Carousel is the best way to experience Instagram on your Mac.
SauceNAO - SauceNAO is a reverse image search engine.