Question about reusing other people's art (original copy cut from a commercial comic book)

OK so, I have been making proxy cards and tokens for Magic the Gathering for my personal use by cutting out art from photos, comics, etc that I bought and own. Obviously I don't feel morally or legally wrong in that.

But what if I were to sell such an item? Keep in mind, I am NOT reproducing anyone's art. I had bought it either secondhand or from the comic store or wherever. Artists, how would you feel about that morally? And is that illegal to do?

I would not feel morally right reproducing someone's art, but this feels like a grey area to me since I'm using something I bought that they made. I make music but I do not yet have any visual art skills beyond having taken a graphic design class.

Most people making peripheral MtG stuff only sell creature and artifact tokens anyway to avoid being sued by Hasbro, and release their art/designs as images that others can print for free.

It probably just boils down to "ask permission" I guess.