Sample file:
http://asavage.dyndns.org/Marc/Road_Trip_M...11/DSC_1936.NEF (12MiB)

This image is 4288x2848.
PMV displays it as 160x120. This is what the EXIF information indicates, but it's wrong nonetheless. Irfanview displays it at the correct pixelcount.

PMView does not yet support RAW files. You see the EXIF information because PMView's "corrupt file rescue" kicks in and finds a valid TIFF (EXIF) thumbnail among all the "garbage" that it does not understand. The Thumbnail size is 160 x 120 and that's the only part of the NEF data that PMView currently can decode.

Remember that PMView was made 25 years ago when it was very possible that downloaded files were corrupt. PMView tries to save whatever can be saved because your phone line was bad, etc.

Modern software has none of these rescue features because people don't see the value of it any more...