I intentionally leave my art to download (without watermarks or a personal signature) for exactly this purpose, I want it to be able to be used and appreciated. However, I most certainly do not appreciate people reposting it on a site like flickr without giving a link back. Personal blog? Sure. You're website? Ok. (as long as they link back and don't claim it as their own) But Flickr? Flickr is for original creations, not reposting cool stuff you find.
This happened here: [link]
Also, if I had known that Media Overload would have become so popular (try a google image search for "media overload"), I would have made a better version of it. The inconsistencies in it are bothering me.
On another note, OneRepublic's new album is absolutely stellar.