What follows is a list of pages, each containing 100 "unique" images in 1024x768, 400 images in total (the individual files are quite small, 532 bytes each). Each image occupies 2,25MB of memory (1024*768*3 bytes, assuming a 24bit truecolor display), each page therefor occupies 225MB. All pages together occupy 900MB of memory.
Similiar memory requirements are needed for 25 open tabs, with 30 800x600 images in each tab.
To reproduce, open each image set in a separate tab/window (closing the tab/window correctly frees the memory in FF 1.5.0.10
You can also browse the pages in a sequence, to see that the images stay in the fastback cache: Previous | Next