I haven't used this in a long time since Google Images came out, but this is good if Google Images doesn't have what you're looking for.
From the page: "Ditto provides visual search of the web using pictures."
Ditto.com is a leading visual search engine. Ditto enables people to navigate the Web through pictures. It is far easier for people to find what they are looking for when they are looking at it! Pictures are fun, fast and intuitive.
The premise behind our company is twofold; deliver highly relevant thumbnail images AND the highly relevant web sites underlying these images. In accomplishing this task we have compiled the largest searchable index of visual content on the internet via proprietary processes.
Great site to find images...