@RafaPunk
I'd say first upload them to a box or mediafire account. I can take a look at them to see if they are, but the final wordwould be from a Cover Admin.
For a game not on the list, post it to the game above or below where it should be. They will probably take a while to be added by a admin, if they meet the standards.
For now, upload to Box or Mediafire so people can download the full cover from here.
A suggestion . . .
I'd say for Skullmonkeys, you should probably use different art. That art is more for The Neverhood 1.