This will draw fire, but I’ll say it anyway. For goodness sake why don’t some folks resize those photos before they load them into their messages! 550x412 will show us the same thing as those monster 1240xXXX plus photos that take forever to load. When I hit a promising sounding topic that is loaded with those things, I immediately back out. It doesn’t matter how good it sounded, and I can’t be alone in doing that!
The same can be said for putting large photos as part of your sig and expecting the server to cut them down. It still takes just as long to load.
There is a very simple answer to your question: Just because people can buy a digital camera, it does not mean they know how to resize images. Most digital cameras come with software but I don’t think all of it will do resizing. I’ve seen many questions on photo newsgroups by people asking how to make their photos smaller.
Of course it could also be laziness!
As to the large photos in members’ SIGs, in my preferences for this forum I chose not to see the SIGs. Makes things load faster and without the irritation!