What are the restrictions on the types of images we’re allowed to use? I’ve succeeded in finding public domain images for the puzzles I’ve made so far (or I’ve stolen from other Tanga puzzles or made my own image), but there are some ideas that I’ve had that would work best if I can work in bits and pieces of copyrighted material, but I don’t know what the restrictions are on my usage. I’ve seen different explanations on what constitutes “fair use,” but I’m not sure how to apply it to Tanga puzzles.

For example, say I want to use a box of Lucky Charms in a Cryptopix, but with the word “Lucky” blanked out. Can I do this? I know that this sort of thing is common practice for Tanga puzzles, but I didn’t want to use that as an excuse. Also fairly common is using a recognizable picture of a celebrity, presumably without their consent, which technically seems to go against the Tanga terms of use.

Does anyone have any idea of what guidelines I should follow in choosing images for puzzles?