How do I change the .rgn files to alter the borders of a Yahoo messenger skin?
First you want to make the .bmp borders the shape you want. Then update the .xml to match the size of your new .bmp borders. After both of those are changed and saved simply delete the .rgn file to the associated border(s). Refresh the Yahoo messenger skin and Yahoo will create a new .rgn file to match your .bmp border. You must do this everytime you change the shape and/or transparency of the .bmp border.