I am really annoyed by the huge images in some linuxfans users’s signatures when surfing the forum, so I decided to hack a user script using Greasemonkey before the moderators of the forum takes any actions.
The XPath is really powerful to manipulate the HTML DOM tree. The signature image is in the the last span element with class attribute equal to postbody in the td element:
allElements = document.evaluate( "//td/span[@class='postbody'][last()]/img", ...
You can download this user script from here. Of course, you need to install Firefox and Greasemonkey first.