Rules are what KyoZz posted in the OP but on top of those you have to follow GAF rules too. I imagine if it's spoiler tagged and has a NSFW warning it's fine, but you might want to check with a moderator about it and also KyoZz as it's his thread and he might not want things to go too far in that direction. It's a pretty SFW thread with the odd hyper-violent image but nothing that someone walking by your office while you're taking a break might see and make assumptions about.
That last line puts it into perspective. I was going to post a nude shot of the character model in CyberPunk, because all pervi-ness aside, it is actually incredibly detailed, but I'll refrain. Thanks!