Out of about 5 or 6 forums that I regularly visit, this one is 1 of 2 that use restricted width, and I'm very glad that it does.
The full width forums are a nightmare to read as they are stretched across the full wide-screen width of your monitor.
I've even asked the other forums to change to a format like this, but to no avail.
So here's hoping that the width isn't messed with.
It's just more user-friendly as it is.
Regarding images being posted that disappear off the side of the forum, it's possible to have some forums automatically resize the images to a specified maximum for viewing in the forum, and to have it clickable to open up full-size in a new page.
As for Chat, I don't bother with chat on any forum.
It's just not something that interests me.