Cover thumbnails should maintain the dimensions of the original image

[salty-horse]

I tried uploaded a non-square cover for the game. Due to the large file size, I converted it to JPEG.

The thumbnail had ugly black bars at the top and bottom. When it used a PNG (after reducing the color space), those were transparent bars, but at least it looked better.

In either case, I don't think the thumbnail should be forced into a square - if it's a rectangle, will it cause some problems with out it's displayed in various pages? If so, those can be fixed on a case-by-case basis with CSS.