You must have Netscape 2.0 or higher or an equivalent browser to see motion. The picture will not move properly until all of it has loaded. In the lower left of your screen in Netscape, perhaps in a different location in other browsers, you can see the percent loaded. Only after it says "Document Done" will the full effect of this very brief little .gif movie be seen.
Note that you need no plug-ins of any kind to view this animation. It is a .gif animation, made from three of the still photographs of Robert Plant that you see opening the various kinds of Top 100 Led Zeppelin Moments.
This animation was made by a very non-technical person (Jean Lorrah) with GIF Animator, a shareware program. Sadly, it is no longer available, and I lost the use of my copy when I got a new motherboard for my computer, and the program could no longer recognize my right to use it :-(.