Simple script to fix the GBA tile data output by Pro Motion 6.5

fix_cel_tiles.lua

-- example usage:
-- lua fix_cel_tiles.lua old_tiles.cel new_tiles.cel

local inpath, outpath = ...

local infile = assert(io.open(inpath, "rb"))
local outfile = assert(io.open(outpath,"wb"))

local bytes_per_tile = 8 * 8

while true do
	local tile = infile:read(bytes_per_tile)
	if tile == nil then
		break
	end
	outfile:write(tile)             -- write 1 tile
	infile:read(3 * bytes_per_tile) -- discard 3 tiles
end

infile:close()
outfile:close()