hi,
If you have a 512 image and want to 2048 you have to select 100% resize (that means no resize) and bsrganx4. The resize before upscalimg option goes from 1 to 100%.
VRAM/RAM is a limiter for GPU VRAM but if needed the app Will use system RAM as GPU Memory to avoid full Memory errors.
The output file is saved in the same folder of the original file, called "filename-BSRGANx2.png". The temporary files in source are deleted once upscale process in done.
Strange you are finding this problem:
what is your PC specs ?
what is your image extensions ?