Here's where I jump in and mess things up. The most disturbing thing here is that being from different countries the legislations people refer to also differ, even if in the case of copyright laws (and especially EU directives) they tend to be somewhat coherent. I'm speaking for the behalf of Finnish law *SHAKES FIST*
First thing: You can't just go and publish something you've found published by other people. Doesn't matter if it's been made available "for free", be it painting, movie, record, article, website, photograph or whatever. Yes, you have your rights for personal use, but publishing isn't something I'd call that.
There are, of course, exceptions (and limits to exceptions and exceptions to limits of exceptions), such as educational or scientific use, citations, articles about the work in question, etc. But just to publish other's works "as is"... no way.
Second thing: Comparision to computer programs are... well, stupid. Most of the "free" (free as in "free beer") ones are published under a certain license, in which the copyright owner waives some of his rights. Or actually does not waive, but grants some "extra" rights concerning the use of it.
This would be so much easier if I could speak (or write) English. Let's make a NS-flamebait: Adolf Hitler made some quite tolerable paintings.