Ok lots of comments here and I not going to try to quote them all and respond individually.
What I am focusing on is processing time. The amount of time it takes to generate the html that is then sent to your browser. Image issues and stuff like that, which absolutely do have an impact on page "speed" are outside the scope of what I am doing right now. That is our biggest problem with site speed. If you need that proven to you, then go to the wiki and create a page that has those same 5-6 ridiculously sized images in it and then load that page. It loads MUCH faster, running on the same server.
The image size (or attachment size) isn't really an issue when it comes to processing the page. That only becomes an issue once the page has been processed and is being sent to you.
Putting images in spoilers does not increase page speed. It actually adds a few k of code that has to be processed.
We have all kinds of issues like CSS that is not very optimized, plugins that may not be playing well together, lots of stuff. Restricting images and the like is not going to solve our core problem when we have php problems.
Probably the best way I can demonstrate the difference is something I bet a lot of people do not know. On Chrome, when you click on a website there is a little circle in the top of the browser bar that spins. Watch it, because it changes direction. It spins counterclockwise when you first click, its waiting for a response from the server. When the server finishes processing that page it sends a response to your browser. When it gets that response it spins clockwise, and spins clockwise while it is downloading the actual page. So go to the
forum index and click Reload.
All that time it is spinning counterclockwise is what I am working on. All that time it spends clockwise is download time. When we get the first fixed, the second wont be nearly as big an issue. For the people that insist on posting huge images, we will have to have some conversations. But restricting images by type flat out isn't going to work as most of the site files are png. People just have to be told to use some common courtesy. Just like people have to be told once in a while THAT IT IS NOT COOL TO TYPE IN ALL CAPS.
Internet etiquette is learned, just like every other courtesy you can name. Some people have just never been told. If I have to tell moderators to just start editing images out of posts and telling the poster to repost them in a more user friendly fashion, I will. But realistically anytime anyone runs across something like the one linked above they should post about it, just as you would if someone posted in all caps all the time. It shouldn't be just moderators that mention that kind of stuff.