The latest netscape (version 2) is fully conversant with the GIF89a, which can have multiple images in the one GIF file, an option not normally used. These images can form a animation sequence, and netscape v2 will display this animation without the need for java, server pushing, or any other wierd and complex arrangement, and does so with little load on the client system or the network (once image is downloaded fully).
Other browsers, not understanding this special GIF option, would only display the first image within the animation, and ignore the rest. Java animations on such browsers just result in a blank space, so GIF animation is much better and cleaner.
Yes. All netscape needs to do to perform some animation is to download a GIF file which has multiple images in it forming an animation.
To stop animations, press ESC or STOP after page has loaded.
Have a look at this fancy banner using a number of multiple stars rolling all over.
The animation of course becomes even faster if the GIF animation only changes the part of the image from frame to frame (IE not the whole image).