does it madder if i make a background in paint.net then pixle-ate it?
and you want 32x32, not 64x64
also, a brief desc of your game, or the game setting(ie. happy, gloomy)
desolate, alone
use the "tiled sprite horizontal parallax" on all three, each with a slightly different speed, and all on the same layer
these ~might~ be 64x64
it's better to use a 128x128 image and then shrink it, as it would produce good looks on a small area(try grid 32x32 grid setting)