I would assign a number to each tile image (01021.jpg)
Then just use an A0A to store it. If the maps are big might be able to use a PDL to gain some efficency or even just store each map row as a packed string. The later would certainly take less memory then an AOA of numbers. You could do the map storing, munging in XS as well and gain much speed and lower your mem consumption. Hope this helps.