Did you notice that Google image search has improve its intelligence. Now it is capable of identifying the image colour. You can filter the image result by colour. That means Google is capable of reading some information from the picture. Quite interesting option
For example if you search for shirt, you can filter the search result by choosing one of the nine colours available. It is working. Try your self.
Before Applying colour filter.
After Filtering Apply
What do you guys think?