I found a bug in Donut Mod

Hi, i usually play the game with a 1366x768 resolution, that matches my computer's, but if i play Donut Mod the phonebooth frontend background
is squarish and does not cover the full game screen, only adapting with a 800x600 resolution. Please fix this by enlarging the background to match the full screen's space. I hope this will be fixed in DM4, for ones who use higher resolutions for the game.