your trying to view em from the floppy disk, is there any space left on the floppy disk? this is an app i never used, so i am uncertain of its characteristics, but it is possible without any left over space on the floppy disk, that it can not create a temporary "preview" file on the floppy, therefore it fails to create a "preview".
try saving a small picture to a new blank floppy, and see if it previews then. If it does, then the solution is that you just need to save the images to the floppy, but keep a working copy of the images on the hard drive.