I've noticed pages/posts expanding beyond the limitations of the layout (this has bothered me personally in my vBulletin installation). So I went out searching for the fix...and I found it, here's the auto-resize fix.
in the following file
includes/class_bbcode.php
Find in line (about 18xx)
PHP Code:
return '<img src="' . $link . '" border="0" alt="" />';
Replace that line with the following line.
PHP Code:
return '<img src="' . $link . '" onload="if(largerThan(this.width,700)) {this.width=650;this.alt=\'Click here to see a large version\';}" onmouseover="if(this.alt) this.style.cursor=\'pointer\';" onclick="if(this.alt) window.open(\'' . $link . '\');" border="0" />';
This will automaticall resize and output the images, if clicked on, they open full size in a new window.
Of course, change the width in "this.width" definitions to fit your layout.
While this may not be the most efficient way of doing this (especially for the end client) it still resolves the issue. Other options include more sys resource intensive solutions, involving ImageMagic or some other form of server side graphics manipulation.
If this doesn't work, I may have accidentally skipped a step...I'm trying to remember if there's anything I may have missed.