A free service (best kind, right?)
You can find it at www.linktiles.com
You upload the covers of your books, or your avatars, or whatever jpeg or gif that relates to you. You include embedded links to your website, your publisher, wherever you want interested folks to go.
The object of LinkTiles is that it's a concentration game. If LinkTiles chooses one of your pictures to include in their game for that day, you get an email letting you know.