It all really depends on what you want to do. Usually, breaking things up into smaller parts is a bad idea, unless your image is larger than 2048x2048.
If you want to go with the detailed image, just put the whole thing into a tiled background and leave it as-is (unless it's larger than 2048x2048 pixels, but to save VRAM it should be much smaller anyway).
If not, then just go with the simple one.