Get it? That's a double entendre..
I have had a number of people ask about stock usage policy - and I thought that it was more explicitly defined by deviantart. It's not as strong as I thought - so here's my preferred model:
1) You are free to use my stock for any non-commercial work posted on deviantart.com without obtaining my prior consent. I do request that you
a) credit me and link to the work (a link to the actual deviation so that people can see how it fits into your deviation - information I am curious about when I look at a photo-manipulation)
b) send me a message or leave a comment on my original stock photo so that I can see what you've done with it. I post these images as stock because I want people to use them, and it makes me feel happy inside to see my art taking on new, often better, life
2) You can make your deviation a print so long as all the above rules are followed and you do not sell more than a few copies. Let's say, 3.
3) You can make your deviation a print if you feel that you have added considerable artistic value and your work no long resembles mine in an obvious way. Please request consent before making your deviation a print in this case. I trust you know what I mean - I just don't want other people selling my photo with only slight modifications. That'd be kind of a rip off.
4) You can use my photos for a school project so long as using a photo from an external source does not violate the terms of the assignment. Please let me know if you use my stock in this way.
5) You can use my stock in a piece to be featured outside of the deviantart community if you get my permission before hand.
I'll add and refine this list as I come to a better understanding of what I'm comfortable with, and what I want to empower others to do. Please make suggestions/ask questions !!!