All of my photographs are FREE to use as reference for personal use in drawings and photo-manipulations. You need not worry about crediting or linking back to me. (but if somebody accuses you of "stealing" a pose or some other bullshit it might be a good idea to keep this page bookmarked)
But I do have 2 rules!
1.DO NOT copy/paste my photos and claim them as your own. You MUST change the image in a significant way. Don't just scribble something like your name on my photo and call it good.
2.DO NOT use photos of my pets/animals in pornographic photo-manipulations (using them for drawing refs is fine).