4:3 Resolution will cut the left/right side of images on a widescreen resolution

[Raildex]

When a (custom) level has loading screens that are 16:9 and you play on a 4:3 resolution, the game will cut off the left and rigt side of the loading screen.
If the image contains credits or the like, they are not fully readable.

[rr-]

The alternatives include letterboxing or ignoring the aspect ratio, none of which are ideal. Best we can do is to open this choice to the builders.

[Raildex]

letterboxing is probably the "safest" option because it preserves the aspect ratio of the original image while maintaining readability