I created the files (now up to 30000x23514) in Photoshop. This is the largest size it can save as a jpg/png/bmp. I'm saving as a bmp so that there's no computational overhead to compress/decompress the 1.3GB file.

Here is the content of the .bat file. I modified the amount of memory until it would work for me. I had it at 8192/16384 but found it paged EVERYTHING to my drive and went from taking about 12 minutes to process to taking hours (before I quit). The values now (8192/8192) seem to work and processing is fairly quick (IMHO).

start javaw -Xms8192M -Xmx8192M -jar gmapimagecutter.jar
exit
Beyond that, I run the batch file which loads the program (gmapimagecutter.jar) with the memory options set.

That lets me then load the big image file. I think that .bmp files also have a 2GB limit in size, which means I couldn't have a 30000x30000 file which I did try. I think that comes in around 2.7 GB.

I have it set at Max Zoom Level 8 in the image cutter program. This produces close to 1:1 representation. It actually zooms in a bit farther, but I can live with that.

I hope that works for you.

Oh - for the record, I use Vista 64 with 6GB of ram. I don't know if this program uses more than 4GB itself or not.