> They don't have to be square
I'm pretty sure they do. If you don't want to waste space, that is.
Nope, it's fine, but both the width and height do have to be pow2. If square textures were forced, then a long thin strip image would waste tons of space in a square but far far less when non-square. OpenGL and Direct3D have no problem with non-square textures.
Just did a quick test in construct
128x512 tiled background = 0.25mb VRAM
512x512 tiled background = 1.00mb VRAM
So works fine in construct too. So if that was what he was looking for, he should be ok with that.