High Resolution ScreenShots for YouTube Channel Art?

[P00t1sdr4g0n225]

I'm trying to make a screenshot to use as channel art for my YouTube Channel, but YouTube recommends images that are of a higher resolution than my monitor supports. (Youtube recommends 2560x1440, my monitor is 1920x1080) If you try to submit an image smaller than the minimum of 2048x1152, YouTube will straight up reject the image, so is there perhaps a way to increase the resolution of either the screenshots or Gmod?

EDIT: Found out about Dynamic Super Resolution.

[lorjason34]

You can do it indirectly without Gmod. Get photoshop (I prefer GIMP), and you can set the size to YT's recommended without losing half of quality on your picture.
To do that (and this is for gimp if you're gonna use that), select all (the whole picture), then go make a new picture, set the resolution size to what YT recommends, and set the background color of RGB to Transparency or Transparent. After that's done, paste the picture in, and select the scale tool, and then resize it to the YT resolution of 2560x1440. Make some adjustments, and export as jpeg or png, and that should do it.
Hope this helps.