How does OOO feel about artists selling prints?

Thread title, pretty self-explanatory. I was thinking of throwing together a few small pieces, maybe drawings of NPCs, generic knights, armors sets (maybe the Hall of Heroes guys), stuff like that, to sell as prints in the future. But I do understand that fan art can be iffy, especially with smaller companies, and I wanted to make sure it was okay before I ended up doin' something bad. ;3
Also idk if this is the proper place to put this so I'll also ask: what kinds of prints would you be most likely to purchase? Smaller pieces, poster-size, which characters, etc?
Thank you! <3

I considered sending an e-mail first, but didn't want to bother 'em if it was known around the forums first. But I suppose a small e-mail can't hurt. :D
I thiiink I saw screenshots of your game around Tumblr. I was wondering how that was coming along and glad to hear it's still in progress!
Some of the prints I am thinking of doing first are very small, like, photo-sized, so they'd be very affordable. $2-3, not including shipping, but then that's still $5 or under. If there's interest in bigger pieces I'll look into that more too. Thank you!

So I had somebody contact me regarding this thread and if I got an answer from the devs, and I did! Didn't think to post it here but I can summarize:
As long as you do not use any of the game's assets (icons, screenshots, etc - anything not made 100% by YOU), you're safe. :D I'd still personally contact them if you're uncertain as it wouldn't be very cool to potentially sell something not-quiche.
If you're looking for a direct question, I'll point you to this page. This way, you can usually get your answer ASAP. I got the okay to make a fan game a while ago (which is, btw, still a WIP. I'm struggling to get the engine working!), but that's a bit different because I wouldn't be selling anything whatsoever.
Also, I would probably like a smaller piece, but that's not saying I could necessarily obtain means to get one of these prints. Good luck!