Of course! The more system resources there are, the better.
We will take graphic resource suggestions into consideration, but because of legal reasons we have to check the author, source and license ourselves to decide if we can use them. Resource uploads are now active for premium players – so if you want to stand out (which will become more and more important), upload your graphics to your account. That way only you can use them and the legal issue should be solved, as you have to accept our Resource Upload Agreement beforehand.
However, if you really want to contribute I suggest you make an account on OpenGameArt.org or DeviantArt and submit your art there under a license you see fit; or if you have your own homepage, you could put it there with a short text that explains the rights of usage for third parties. That way we can always link to that source and credit you appropriately.