Quote Originally Posted by caspertone View Post
...I cannot use MapEdit to adjust levels... as the IMG is to big for being loaded in MapEdit. I need to cut the IMG so that it can be processed by MapEdit... but for that it would be convinient to solve the levels issue... by now, chicken/egg...

Yes depending on size the .img sometimes needs to be split into it's individual, smaller tiles in order to be loaded into GPSMapEdit.
In the screenshots above I used the free Australian [Only registered and activated users can see links. ] for that example.
The full ShonkyMaps map consists of 366 individual .img tiles joined to create a single .img that is a complete map of Australia.
I used GmapTool to split, once loaded I set 'Create' to 'Single Maps' on the 'Split' page after choosing a location, then clicked 'Split All'.
Once split then I simply loaded one of the tiles into GPSMapEdit & took the screenshots.