Hi KM,
I'm trying to understand what you mean by "splitting to sheet sized resolutions 8x11".
Do you mean that you want to print it on multiple 8x11 sheets? If so, Qimage has a "poster" feature for printing an image on multiple sheets. Qimage takes care of the resolution automatically.
Terry

That depends on your computer resources rather than Q-SE
If you click Help in Q-SE, click "Analyse Current Settings" with the shift key held down, you get information on the largest image size that can be handled by Q-SE on your system.
For example, on my W7-64, 6GB RAM machine the figure is 2000MB.
I think the "size" is calculated from the image resolution, ie.(H pixels x V pixels)x3/1000MB. The x3 is for RGB.

Tell us what resolution the (500MB) image is? can it be produced at a smaller size?
Sorry I know nothing of GIS files other than what I saw from a quick glance at Wikipedia.
Terry