treeline - 10:34 pm on Jan 5, 2005 (gmt 0)

In my version of Firefox (1.0) this wasn't the default option, and it's easy to have unchecked. Just check load images, and don't check the originating website only button.

Tools > Options > Web Features
[x] Load Images
[ ] For the originating website only

Some people load ads this way, and the advertiser handles the details. Others don't want to use the bandwidth, so "borrow" it from the other site. The best reason I can think of to select the option is that it would probably avoid quite a few ads, but other content would be tossed out as well.