What software are you using to build the backgrounds/maps? I have been using Gimp but there is a ton of room for error and having it consume more memory with offset tiles.
So I been using a lot of free sprite / tile packs, but I've been modifying them in libresprite since it's free. Once I have those, I import the tileset in to tiled. I'll then create a new map in tiled using that imported tile set.
