Renderosity is in Nashville. This is the state code concerning public displays of nudity.

http://www.michie.com/tennessee/lpext.dll/tncode/11665/11985/11aac/11af0?fn=document-frame.htm&f=templates&2.0#

Renderosity allows you great freedoms for free. In return they ask you to obey the laws of the state. If you don't, it's their butt on the line. They can be fined and their property padlocked until such a time as the case actually makes it to court. This could mean no renderosity for anyone for 6 months to a year.

A child will see the generated thumbnail before it ever get's stopped by the content advisory on the main picture. Adults who find this image offensive can also complain. This violates the criminal code of the state.

For the first render I don't see why it can't be posted if you include the appropriate content advisory and make either a generic thumb or use a portion of the render that does not contain nudity. It's not the mod's responsibility to do it for you.

On the second stick figure image the mod may have inserted the content advisory thumb for you. I don't know because the forum software doesn't do it. The image still violates state law and the TOS however. The blue stick figure could be mistaken for a man with an erect penis, especially if the viewer is very poor sighted, perverse, or lonely. You can erase the angled line and two swirls at his crotch, redraw the line bent, or cover it all with a cartoom fig leaf. This would then meet the TOS. It really doesn't matter how bad a representation it is. Mr. Stiffy violates the rules.