There is something odd about the colors when a file goes from Macintosh Claris Draw into X11 and GIMP. The "flashed text" in the animated gif should be red and green. If I am going to use GIMP I'm going to have to read the documentation...it is not conventional Macintosh software.
After finding how to view the layers of a GIMP image (no, you do not open the layers window from the windows menu! You open the "layers dialog" from the main file menu) and paste content into layers (no, "paste" does not do it, not even "paste into", that just makes a floating layer...you have to right click on that and "anchor" it) it was not too bad. Many thanks to yeoman on #wikiversity-en!
The X11 installation into Macintosh OS 10.4 was no problem.....it is an option on the install disc. There was a fat 55 MB update waiting in software update. The GIMP installation (Gimp-2.2.11.dmg) was a little spooky with it wanting to swap out one of the X11 files right at the start.
I updated Portal:Media to the "editable box" format.....that's number 10! This particular portal took extra time because I decided to try to make the animated gif using GIMP (see above). This required that I find the software install disk for my Mac. Not hard, but I decided that it was time for New Year cleaning of the entropic mess that had accumulated in all the CDs and DVDs. Also, I decided to backup the old hard drive (4.3 GB for 2006) and repair permissions on the HD.