TinEye is a great little tool if you are looking for images based on colour. This web based app has extracted colours from 20 million Creative Commons images on Flickr to make the images searchable by colour.
You can select up to 5 colours and you can also add tags to refine your results. Here are some examples:
Once you have the correct colour, you can click on the image, which takes you straight to Flickr to download. Don’t forget to attribute the original work using a Creative Commons licence. Why not try it yourself?
Image: Screenshot from TinEye labs based on the colour yellow