Only problem is that the game could be held responsible and there are people out there that will push a law suit saying the company did nothing. Now if there was a filter system for names and images then yea.
trust me i did a lot of illegal stuff on the internet, that's not how it works , if there is a claim (which must predate any type of legal action) then there will be a warning sent to the company or the user - which ever or both, then you have months of processing time and finally if still nothing happens, THAN they can try to find a lawyer to take your case in a situation where you have nothing to gain and very little chance of winning , but you spent a lot of money on nothing ... this is not as easy then a slip and fall at best-buy or burning your self with your hot beverage in mc donalds, on the internet you can get away with a LOT and not much will happen legally .. hell i cloned the domain name of AAA (american automobile association) to sell credit cards, right with my own name address and all on the domain registry, after a year they email me threaten me me that if i wont stop doing it they will sue me, i told them to f off, we ended up after like 6 months back and forth they offering me $15 to buy my domain name, i told them i go for $1000 because i know for a fact that the starting price to reclaim a domain starts at $2000 so i save them 50%, they did not go for it, but by that time some months later i had other ventures and the website went down simply because i stopped paying for the hosting, the hosting company btw told them the same thing with out a court order the website will stay up, i did the same with mastercard too byw they did not argued they just paid the $2000+ and eventually they got my domain , no other consequence to me, private citizens have even less rights and resources, nothing will ever happen legally because of a picture
... this is just one example of many many different illegal activities i done in my youth on the internet, its not as easy to sue people as you think, suing people cost time and money, and they might not see a return at all , and who decides if its even worth it is the layer OR they have to pay up front big bucks ... the police will do nothing unless you sell drugs online or pirated software and even that takes sometimes months to years .. just look at that famous pirate site every one knows, it will never go down
so trust me a few inappropriate images is no risk to anyone
the player would risking hes account being banned by a GM, and you have to deal with an inappropriate picture for a while .. so what ?! whats the big deal ?!