I'd advise against putting effort into that method, if that's your reason for doing it. I don't think that would be a solution to the 1 user's problem. There are ways to re-do your tiled map into a singular JPG, but it's clunky. You could assemble it in Roll20 and screenshot it, or you could download the tiles individually and re-assemble them in Photoshop or the free program GIMP, then save and re-upload. Not worth the trouble unless necessary. Look into helping the 1 player troubleshoot what the bottleneck is, or, if the investigation proves that their computer or connection or wifi is simply slower than others, then they just need to learn to Wait patiently for the map to fully load. They should optimize things like shut down other programs running in the background. Turn off their Netflix downstairs that's on the same broadband connection bandwidth. Something like that is more likely to have a noticable impact on 1 player. Yeah the advice to mash-together your Tiles IS a good technique if you have/need/want to use dozens of tiles with perhaps dozens or hundreds of trees and rocks tokens. It's not likely to be a big time-saver on loading for 1 player when the other players are all already proving to load the tiles just fine.
