About my works here:
Rule 0: (For most lazy people) Most important rule is: let me know if you used/want to use my work.
1. Personal use: I have nothing against using my photos as desktop wallpaper, or even printing them for your own use, as long as you use deviation (watermarked) version and not a print preview (I will consider using print preview image an infingement). I would like if you let me know that you like my work, but it's not a requirement. I can also make specific size wallpaper from my work on request if I only have a file with sufficient resolution available. Just drop me a comment.
2. Non-commercial use: this includes derivative works, like photomanipulation, web layouts, skins, school projects, as well as publishing on wiki or picture post. Basically anything you don't make profit on.
a) Work with Creative Commons license: just follow license rules. The form of attribution I require is:
  - Visible picture or text link back to either deviation or my deviantArt page in case of online use. For offline uses: if present, watermark on picture is enough, otherwise info about author (I prefer my real name in this case: Krzysztof Lis), if possible.
  - Deviation comment or a note to me linking to whatever you did using my pictures. In case of offline use, a brief description.
b) Copyrighted work: see point 3.
c) If you need higher resolution, image without watermark, etc, contact me. For best (and fastest) result, describe not only what you need, but also what you need it for.
3. Commercial use: contact me before you do anything. I will require to know what you are planning to do and whether it is profit or non-profit. Then we will come to agreement. I am sensible and not all-about-money. I can also offer higher resolution, source files, in some cases even my help.
4. Gosh! You did something before that journal was posted. What's going to happen now?
a) You let me know. After that it's like point 3.
b) You don't let me know. Some day, maybe even tommorow, I will find out. Then I will bill you high, at least.
5. Any case of plagiarism or identity theft will be dealt with mercilessly.

Final statement: I support free culture. I believe in individuals right to creativity and to share knowledge they posess. I also believe that claiming and making profit on someone else creation is a theft. But I also believe that monetarization of art and knowledge hurts culture and slows down progress. I do not believe that fair use and second hand market equals piracy, nor that companies have the right to steal from individuals. Be warned that in the case of latter I may not be reasonable and aim for your company loss rather than my profit.