The original GIFmerge program was written by Mark Podlipec. It was then modified by Rene Mueller (kiwi@iis.ee.ethz.ch).
For a while I could not locate the program.
I kept a copy of this useful program and provide it to you here:
GIFmerge as a unix tar file
Current official source:
Schneider Lab
origin: 1999 Jul 26
updated: 2012l Feb 02