= Small mods that change the visuals =

The standard image for scenarios and multiplayer maps is universal, but your mod repeats cases with campaign images and fan-made scenarios in standard and multiplayer modes. It's not universal. The image doesn't adjust.

Maybe it's because a different resolution is selected in the game?

Added after 9 minutes
The fact that they somewhat repeat campaign art isn't that bad. It's the least of the problems. I'm much more interested in the second point – adjusting to the resolution. I still think that most players are already playing with a FullHD resolution or at least a 16:9 aspect ratio.