Weblog Google Operating System points out a new search option in Google Image Search that filters images by colour. Colour search isn't available as an operator yet, but a simple URL hack will do the trick. To start searching Google by image colour, all you have to do is append
&imgcolor=colorname to the URL of a Google Image Search—where
colorname is replaced by one of a number of colours of your choice. So, for example, your search URLs might look like this:
This isn't the first time a search engine has added support for searching by colour, of course. Previously mentioned apps like Multicolr, and Yotophoto all aim to do the same, but in a more specialised way -- it's nice to have this functionality built into Google.