Firekit, it means your signature exceeds 420 pixels and you need to remove something out of or edit your signature in order to put it under the limit.
Here's a walkthrough of how to check if your signature is under, at, or over the limit. If this is well enough, perhaps Ellie will put it somewhere on the first post or something.
First, take a screenshot of your signature. This can be done by pressing the Print Screen button on your keyboard. On a Mac you hit Command + Shift + 3. From there you paste it onto a Paint application. For this tutorial I'm using Paint.net which is free.
Click for Example
After you've pasted, select the 'Rectangle Select' tool in the tool window.
[img139]http://i40.photobucket.com/albums/e212/smugthewartortle/Walkthrough02.png[/img139]
Now, starting from the very top of your signature, click and drag all the way to the end of your signature and let go. When you've finished there should be a blue hued rectangle over your selection.
Click for Example
Now we have to crop your signature. To do this, go to the tool bar and select 'Crop to selection' under the 'Image' tab.
[img139]http://i40.photobucket.com/albums/e212/smugthewartortle/Walkthrough04.png[/img139]
If you've done everything right so far, the result should be the selection you chose.
Click for Example
Now, look on the bottom right corner and you should see the dimensions of the image that is newly cropped. The number on the left represents the width, and the number on the right represents the height. The one we're focusing on is the one on the right.
In this image, I've highlighted where you would find the dimensions and which of the two numbers we need to focus on. The height of my signature is
341 pixels. Since the height limit is
420 pixels, my signature is under the height limit and is therefore acceptable.
I hope this clears up any issues.