Roblox moderation is infamous for being janky. People have gotten warned or even banned for no reason, and people have gotten away with bad things. The best thing you could do is just reupload the image again.
There is, but it’s on a case-by-case basis. You will also need to reupload with a slight change for it to be accepted. However, if the appeal is successful, they should restore the original asset or give you direct permission to reupload.