Early on, I didn't know how to credit icons in keywords, let alone that I was supposed to, and so I didn't. I didn't also save them with who-made-them names either, so I now have a lot of icons saved to disk I have no idea (or only vague ideas) who made them. But on reflection I probably would get annoyed if somebody I didn't know came and complained. The maker... or somebody I did know... that's totally different.