Don't have Greasemonkey? https://addons.mozilla.org/en-US/firefox/addon/748/
This is a Greasemonkey script for Firefox that fixes a problem with wide images being visually cropped in prosilver.
Many of you are probably using prosilver as a forum theme, being the incredibly smart, snappy look that it is. You have fine taste, my friends. However, you'll notice that the rigid layout doesn't accommodate large images, which makes viewing complaints, picture threads etc. fairly unforgiving.
I've made a Greasemonkey script which – wherever images in posts are breaking the theme's width limit and being mercilessly chomped – will scale the offending images down, so that they fit the page layout.
The images themselves also become links to the URL of the full-scale image when they're scaled down (assuming they aren't already a [url]), so you can click on them to retrieve the full image in your browser.
Images will also be resized when previewing posts.