License

If I were to create something great, and wanted to license it, I would use the Creative Commons Attribution-Noncommercial License.  This license allows anyone to use your work in any way (so long as they credit you) for non-commercial purposes. But if a person wants to use your work for profit, they have to request specific permission.  I think this is a fair, justifiable way of sharing, as long as the end-user isn't using it for profit.  If this is the case I want to know what they are doing with it, and how much they are making off it.  The only thing that could change my mind would be if the "creation" profit was being used for charity or a good cause...not to just line someone else's pockets.

I found this image on freedigitalphotos.net, a site where downloaded images can be used in both corporate and personal projects. 
http://www.freedigitalphotos.net/images/about.php
If you want, you can purchase higher resolution photos from the photographers directly.  I think this photo has great meaning to..."on my last string"...for me...my sanity. **Brilliant**

The author is most likely a photographer trying to receive credits and feedback on his/her works.  That's probably why they put their work out there for free, and if you would really like to use it for higher res projects or printing, you have to pay up:)  I like the concept...it's especially good for people just starting out.  This is generally what I would do, give the public rights to share, but if they want to use for profit, I need to know about it.