Interlaced GIF isn't displayed

[Uday Reddy]

Alan <email address hidden> reports:

I had someone send me an email which when viewed in another email
client showed text superimposed on a background image. In VM the
image didn't show; instead the complaint was
Unknown/Bad GIF image encoding
I extracted the image to PhotoShop and then made a copy. I was
offered the choice of normal row order or interlaced row order. With
normal row order and the copied image inserted into the email in place
of the original (properly encoded), the image displayed. With
interlaced row order and the copied image inserted into the email in
place of the original (properly encoded), the image was not displayed
and the complaint shown above appeared.

http://groups.google.com/group/gnu.emacs.vm.info/browse_thread/thread/05faebf8ce19018e/c1ba131ebcb54772?lnk=raot#c1ba131ebcb54772