I know some message boards have image tags that allow people to type in the size of a picture. Ie. Using height="N" and width="N" to dictate the size of an image. like [img width="100"]<image url>[/img] will make a picture a 100 pixels wide, and the height will automatically adjust so it won't distort the picture.
I'm just asking because, it'll make it easier for people to make sure that their signature is within the 100px height limit. Also, it'll probably help in those screen shot threads as an easier way to thumbnail those huge pictures. Plus, it'll help satisfy my inner OCD, when one pic is a little bigger than the other. :P