Google Images - Google Images is a search service owned by Google that allows users to search the World Wide Web for image content.
Friski - Search your Instagram posts
SauceNAO - SauceNAO is a reverse image search engine.
Dwell - A social network for the design-obsessed
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
Roundio - Explore what people posted to Instagram or Flickr near you