How does Google's image color search work?

Question

Let\'s say I query for

http://images.google.com.sg/images?q=sky&imgcolor=black

and I get all the black color sky, how actua

Answer 1

Well, one method is, in very basic terms:

Given a corpus of images, determine the high concentrations of a given color range (this is actually fairly trivial), store this data, index accordingly (index the images according to colors determined from the previous step). Now, you have essentially the same sort of thing as finding documents containing certain words.

This is a very, very basic description of one possible method.