The L in a TLC Match

Just to clarify, Public Domain means you give up your copyright to an image. That means that credit and/or permission cannot be required. If you want to require credit, you should use Creative Commons By Attribution. Look up CC-BY. Additionally, you can use CC-BY-SA, SA meaning Share Alike, which requires people to release their changes under the same license for others to use. That's what I use for most of my original characters. Just remember you can't apply that license to the character themself if it's one you don't own. There's another addon for CC-BY called NC, or Non Commercial, which you can use to prevent monetization of your work.