Some of us have a great eye for complementary colours and matches—and then some of us still don't understand why brown shoes and black pants are a bad idea. For anyone looking to set an image against a complementary background or find a colour scheme, Whats Its Colour (their grammar, not mine) is a free web app that can help. Upload an image and the site creates a palette page with a complementary background and a list of unique and dominant colors in your image. Photoshop and GIMP gurus might already know how to sift these kind of things already, but the visible colour matching could be a boon for presentation slides or small design projects. Thanks Chris!