I'm currently loving the Tineye
reverse image search engine. BossLady wanted an image of Clark Kent transforming into Superman, and I found one
that's a decent image, but not great quality. I click over to Tineye, enter the URL of the image I'm looking at, and hey presto it pops up 55 results of varying levels of similarity. Sure enough, one
of them was plenty big & sharp for what we need.