Well to be honest, im sorry for those minority of people who have those internet issues
It's not such a small minority.
Up to last week, I was in that situation, since a lighting struck a telephone pole nearby, and I had to connect with 3G for 30 DAYS, the line was restored just yesterday. Since I need to check all the threads on the forum constantly, many times at day to support users, if it's too slow for me, it also affects lots of other users. Alessandro, our main scenery designer, is now connecting with 3G too.
Of course, the rule was in effect way before I had this accident, but it was during this month I realized how painful is to visit a thread with forced inline images.
I also size all my pictures to fit on all standard monitors and they are viewable easer on moble devices such as my iPhone
Posting a screenshot in fixed size (what is a "standard" monitor ? ), instead of using thumbnails, render exactly the opposite effect. Instead, with thumbnails, you can post at any resolution you want, even higher, and page loading speed wouldn't depend on the image resolution and only marginally by the number of the image you posted.
Basically. If I can't put the warning on the title and post the way I like, then that's okay. I'll just stop posting them. So perhaps maybe the rule needs to change if warnings are posted.
This system would be very cumbersome, because it would force you to calculate for *each* different set of screenshots, what would be the total size, because the loading time depends both on the image resolution, and the number of images posted so, just putting a "warning, large post" wouldn't be useful, also because "large" is subjective, depending which connection you use, and if someone pays by traffic, he would want to know the exact size.
And, of course, if we made the rule more complex as you suggest, asking to put a warning, it would make it more complex for anyone, just because you prefer to first upload to a separate server, getting the URL, link it here, instead of attaching it directly.
If you really don't like using Attachments, at least use the URL tag, instead of the IMG tag, so only those interested in the screenshot will load it, by clicking the link. Which is what you end up with anyway, since I always edit the posts with too many IMG tags into URLs