Why don't my reference .png images display properly?

I run DraftSight on two different machines in two different locations.  I can open a drawing that contains .png  and .jpg reference images on one machine and all reference images display perfectly.  I can open the same drawing on the other machine and the .png reference images display so poorly that they are useless.  The .jpg images are fine.

Is there a setting within DraftSight that might govern this?  Both machines run 64-bit Windows 7 and--as best I can tell--the monitors are comparable.  The only inconsistency I note regarding display involves .png reference images within DraftSight.  Or is this a version issue?  The machine that I'm having .png display issues with runs DraftSight V1R4.  I can't upgrade at the moment.

Thanks!