Improved screenshots are on there way
This tutorial will teach you how to advanced borders on your sigs, starting with...
1. Take your sig and make a new transparent layer
2. Select>all - make sure your second layer is picked
3. Edit>stroke selection - make sure your FG color is white at this point - set these settings
4. Stroke this layer again but this time make sure you FG color is black, and use these settings
5. Stroke the layer again but with a white as your FG color and these settings
Your finished sig should look like this
6. Go to dialogs>layers, or ctrl+L set your 2nd layer to overlay, flatten the image and you are done
