Editing campmap maptex

[antidotos]

Did anyone out there succeed in creating a brand new maptex2.tga campaign map.
TGA is a compressed format but when I try to open in an editing software I need more than 700 MB (which crashes my software).
The final image should be around 32768 * 24576 pixels.
Actually I started from the lukemaps (modded) and resized to conserve the shapes (800%) but failed miserably with "not enough disk space...".
Did I mistake somewhere ?
Is there a way round or is my comp decidedly too old ?
Thanks for reading.

[Latro]

Well, the editing bit worked on my comp.
I tried to resize the actual map a bit smaller and add some more bits from Iraq and Iran. In a hope to add a new Persian faction. But I got an error on loading the map.

Does the map need to be a precise size or could you just make it bigger?