Done
I prefer to hold something I purchased in my hands. On the gaming-platform Steam, this is not possible. You can only buy games in a digtal form. I searched for a service where I can only buy covers for games and found the community-page steamgamecovers.com. On this page is it possible to find a game cover which is created by the community. You can print the cover for yourself rand burn the game-data from steam to a disc.
I realized it was a hassle to repeatedly switch between Steam and steamgamecovers.com. Therefore a web-extension would search the correct covers of a game and display it directly on the Steam-Game-Page.