Thank you @mrmarkuz, just what I needed.
To add to this discussion, updating an existing ‘branding.jar’ file is the easiest way to get this done. Here’s a tip for anyone…the following post:
Look at the post from June 22, 2017 on this thread from rhawkins. They have provided their snakeden.jar file. This was a very nice file to use to base my branding.jar file on. Updating with my logo and modifying the html file gives the Guacamole Login page just a bit extra to make it look professional IMO.
Hope this helps someone else!