Testing out the dimensions

Hey guys, Magedark/Allen here. I worked on the dimensioning of the game, and I thought this would work for it, however, I'm going to post it up so everyone can see it. The dimensions are 800 * 400, so I was wondering if it should be bigger or whatever. Also, I'm working on scaling the ground to a nice platformer size.

Is the size for the ground fine, or should I upscale it, or downscale it? I'll make it transparent as the time comes, this is just for proof of concept.

And to the programming guys, when the ground is fully loaded, the entire image is loaded, meaning I can scroll through the entire image. This makes the platforming continuous strip a lot easier to accomplish, but I haven't figured out a way to do it yet.