Read the post on FluxBB.org : New way in managing signatures
This document is a personal reflection on "How to improve FluxBB Forums user's signatures management".
Please keep in mind while you'll be reading that this document is not official.
Currently, restriction in signatures can only be applied to the maximum amount of character and/or lines.

Screenshot of current Signatures management system on FluxBB
The main issue is that even if the amount of lines is restricted to 4 (for instance), nothing prevent users from using king sized pictures that are even bigger than 10 lines ! This is a problem I experienced on a board I'm administrating.
According to me, the best way to improve this without using Scripts or heavy solutions would be to use the CSS property "clip". Instead of "the maximum amount of lines", the administrator would be allowed to specify maximum height and width. For instance :
Html :
<div class="sig-content"><span class="sig-line"><!-- --></span></div>
CSS :
div.sig-content {
max-width: /* maximum width allowed */ !important;
width: /* maximum width allowed, for IE6 only, width is fixed */;
max-height: /* maximum height allowed */ !important;
height: /* maximum height allowed, for IE6 only, height is fixed */;
clip: rect(0, /* maximum width allowed */, /* maximum height allowed */, 0);
overflow: hidden;
}
<style type="text/css">
div#clip-my-ass {
max-width: 400px !important;
width: 400px;
max-height: 80px !important;
height: 80px;
clip: rect(0, 400px, 80px, 0);
overflow: hidden;
}
</style>
<div id="clip-my-ass">
<img src="resources/illu_freedom.png" width="450px" height="450px" alt="Illustration : Freedom is an outdated concept" />
</div>
Result :
(Real picture size : 450px x 450px)

Illustration by Apocalypsedraw - Freedom is an outdated concept
The point is not remove the "maximum amount of character" option if this idea is implemented. When this part of the code only manage what is displayed, the "maximum amount of character" manage the content (that even if not displayed is loaded by the navigator if using only my method). They are complementary methods. In this case, the "maximum amount of line" option would be useless.
This method is cross-browser and cross-platform
Here's some first shots :
By André Loconte for the FluxBB Forums.
Since English isn't my native language, I might have made some mistakes, so feel free to contact me if you find any.