Don't forget that just because you double the image size, that doesn't mean that you are going to fix the root problem of the blurriness. If you take a 512x512 image and increase its size to 1024x1024 (which is 2x as big by 2x as big, so it is really
four times as big as the original), you will just have a 512x512 image blown up and blurry. That 2 pixel wide line on 512x512 is just blown up to a 4 pixel wide line on the 1024x1024. Once you resize the image, you will have to rework the details too. I took his SD40-2 to make my Florida East Coast #714......
You will essentially have to retrace a lot of the detail work (panel seams, doors, etc., redo the rivets, and so on) to "start clean" before you can do a reskin. Remember that these
are publicly reskinnable, so go for uploading your reskins to the DLS!! The resize of the image isn't a big deal. These locos aren't very texture heavy. The original undecorated one is 1.11MB, mine with the resized texture is only 1.3MB.