Then you need to have proof of that. Because if it’s under question at any point, you have evidence that you’re legally allowed to use it.
If anything comes up regarding it’s copyright, and you just say that you were told it was okay to use, it doesn’t amount to proof. Always better to be safe.
Also if you were told you could use it, that doesn’t equal you sharing it as free for others to use, with no copyright or credit attached. That is disrespectful to its owner, as well as could cause others issues. This artist is going to have their work taken by whoever wants to use it, for free, and most likely editing it and sharing it further.