you can use teeworlds tiles in teeclone :O
all you gotta do is edit the tileset image in a image editor
like GIMP and halve its' size so that it is 512x512.
tiles in teeclone are 32x32 unlike teeworlds

you can leave backgrounds like clouds, suns etc. in their normal size.
their size scale can be later specified in the map's background settings :O