[Gimp-user] Q: Opening image with 'excessive' resolution

[John Mills]

GIMP Users -

If I open a large JPEG image file (like a commercially scanned
transparency) in GIMP-2.2, I get a warning message:
 "Image resolution is out of bounds, using the default resolution 
  instead."

The opened file is indeed at a low resolution (72 ppi), and has lost a
great deal of information. Photoshop [Elements] silently opens the image
at 300 ppi and seems to have retained much better detail (textures in 
this case).

The file sizes are not extra-ordinarily large - I can resample to a 
larger size if I wish.

Two questions:
 1. What exactly is GIMP testing here (pixel spacing or number of pixels)?
 2. Are either the maxiumum or 'default' resolutions adjustable?

Thanks for any background on this. 
 - John Mills