Contribute (And Use) Public Domain Images
summetj writes "BurningWell.org is a repository for public domain ("free-for-any-use") images. If you need a high resolution digital image for any use, Browse the Images. If you have produced any high-resolution images that you are willing to place in the public domain, please Read the Donors FAQ."
Don't forget http://www.sxc.hu and http://www.morguefile.com
"It was hell!" recalls former child.
If you want to REQUIRE that credit be granted for your images, then find a site that ISN'T asking for artists to put their images in the public domain. It is mutually exclusive with any form of licensing, even BSD-esque "Whatever you want as long as you give is credit" licensing.
Granted, artists do benefit by a general spirit of openness and collaboration. The important caveat (for me at least) is that derivative works are non-commercial. Since by definition most artistic works are completed works, it doesn't seem right for someone to come along and use your music in a commercial or swipe a design for a t-shirt without anything in return other than the good feeling of sharing.
I like the idea of the texture library another poster mentioned, however. I have no qualms about offering "buliding blocks" for free, even if they are used commercially. By the same rationale, I don't mind sharing field recordings or random snippets or loops for free, as long as I get some attribution if they are used in other works (and hopefully a notice too!).
I hope this clears things up a little bit. Respond with any questions/counter-arguments you may have. : )
harmonious design