I'd like to take a moment to remind everyone that there is a 300 pixel height limit to signatures, including images and text.
Also, if you're linking to images from another website, please be aware of the content on that website you're linking to. It's been a bit of a trend lately to use a certain gif site that creates gifs from YouTube videos... I will not link or name the site here, but if you've used it, you probably know it and have already (or will) hear from me or a moderator via PM. The site contains mature content not permitted under our forum rules, and is, from now on, banned from use in both signatures and posts.
It is not the only website out there of its nature, however... so as I said, please be aware of the images you are linking to in your posts and signatures. Even if the image you choose does not contain mature content, many of these images will link back to the main site which does.
