SnapShot Viewer Image Compressed

I have snap-shot viewer installed on server. An e-mail contains an
attachment of this file type, i.e., Image.snp. For myself - [an
administrator], I'm not having an issue viewing the image. For another user,
when he opens the same e-mail file and attempts to open the attachment file
the images is too small to be readable. It appears compressed. Using the
Zoom feature doesn't help this person to be able to view the file. It
appears the system opens the file for himself in a compressed mode - for
myself, [the same file] it's readble.

What can be causing this issue? Please advise, I'm at a loss to understand
why and need to resolve this ASAP.