Image problem in Imagine (8.7 and 9.1)

Bear with me if the information here is incomplete. I'm a system
administrator posting this for my analysts and have asked them for a
terse description of their problem.

After converting a compressed arc raster product to the Imagine
format, opening that image in Viewer and then panning or zooming adds
black pixels to the image beyond the extent of the window, and to the
image file itself.

Has anyone else run into this?

Thanks for looking.