Reading about a current submission contest for artwork in Open Source land and remember, yet again - why you never ever ever do that.
Nothing, absolutely NOTHING good comes from it. It doesn't improve community relations, it never creates new contributors in the long run and at the very least you'll get people disappointed and some times toxic as well.
What it does do is prove over and over that "Criticism" is a skill, and a skill seldomly possessed by computer enthusiasts.
Always! Empathy and Humanity first, the rest will sort itself out.
To quote Terry Pratchett: "problems begin when you start to treat humans like things"
A quiet, safe space. A great place to maintain a minimal social network presence.