To quote Neil Gaiman:  "the danger is not piracy, the danger is obscurity"... I put all my art under Creative Commons licensing;  I allow free personal use ( including derivative works) with attribution.  I even provide 2000 (ish) width images (one can print a pretty decent 8x10 from these) on my website for nearly all of my images and allow outside linking from sites like Myspace..  I have no doubt that this has helped my google ranking substantially.  My website is usually on the first page of google results.  Not to mention I have had a fair amount of blog coverage.

Am I making much money selling fractals?  no, but I make some, enough to pay for my equipment, and probably  a lot more than I'd have made if no one had heard of me.  Anyway, for me it's just a hobby; I have a normal job.