This thread is definately flogging a dead horse but I'd still like to give my opinion on it.
To LGM about scrolling to look at pictures - why not just write some code into the forum software to scale the pictures biggest edge to 600? That way it stays within the forum rules, means you don't have to scroll and whoever is linking to the pictures doesn't have to do any extra work on the picture. While the picture would still be the same file size meaning that it would take slightly longer for the pictures to load, the majority of users are on some sort of broadband connection and broadband connections are becoming more available and cheaper.
Re pictures in posts. If a Progress thread has no pictures, I'll more than likely not read it. If it has links, I'll randomly click one or two and then navigate away. If a thread has pictures in the post itself and I like the look of the guitar, I will read the posts and possibly (try to) contribute as best I can. Having the pictures do not contribute to PG's bandwidth bill more than a normal link would so costs do not go up. Perhaps some more code could be added to the PG forum software to allow in thread pictures to be viewed as links or as tags.