Is there a repository or link that has resized and properly compressed box art files? I prefer the official boxart rather than the mockups I'm seeing from people. The Google search on hakchi only seems to fetch wallpaper sized images.
That's going to be hard.
Unfortunately, over 90% of the SNES boxarts out there are custom. Most are made to look like the original box, but contain a number of inconsistencies. Usually it doesn't have the company logo, or if it does, it's the wrong logo or in the wrong place. Most of the time the artwork doesn't have the same dimensions as the original. Sometimes the dots on the right of the box don't go all the way down. Sometimes it's missing the ESRB rating, and other times it has it for games that were released before the ESRB. Other times it's missing extra logos like Multitap/multiplayer logos, and the sort.
If you don't mind that they aren't original as long as they look the part, then go right ahead and google them. But if you want them 100% original, it's going to be hard to build up a collection.
The only places to get authentic boxarts is on mobygames, though the lack a bunch of them. GameFAQs has a ton of those fake/custom boxarts, but so far the Japanese ones seems to be authentic.
Nintendo Age (
http://nintendoage.com) is the only place I've found where can find a complete 100% authentic US SNES boxarts collection. I have verified their boxarts for over 100 games and not once I've encountered a fake one. The only problem is you have to crop the front of the box because they scan the entire box.