Recently, there have been a lot of people using huge animated signatures on the forums. Rule 12 of the Animeb Rules clearly state the maximum limits of sig size:

Quote Originally Posted by Rules of Animeb
12. For the sake of our members who do not have broadband connections, please keep your signatures within a reasonable size. Anything under 400 pixels high and 1028 pixels across is fine, and no bigger than a maximum size of 200kb combined. Members with oversized sigs will be asked by a member of staff to resize them. Failure to do so may result in an infraction, so please don't argue about this.
If you are found to have an oversized sig, you will be asked to change it. If you refuse for whatever reason, you'll land yourself an infraction and possible point penalties and have privileges taken away. At worst, you could even get banned. It's a pointless thing to rebel about, so please don't bother. Take after most people, and change it without complaint. It's almost always file size that people are guilty of, so be aware of this when you choose your sig to avoid having to change it later.