For starters, to preserve a .GIF animation for the header image, I want the original image to display rather than a rendered image-style. 

The default image style is Image style: Wide (1090), which converts the image to .webp, disabling the animation.

If you are trying to connect using the Cisco AnyConnect GUI client, and you are encountering an error message that appears immediately after clicking "Connect", you can get more information by exiting the app, and initiating it from the terminal. 

/opt/cisco/anyconnect/bin$ ./vpnui

You may then recreate the error within the GUI, and get more diagnostic information from the terminal window.

/opt/cisco/anyconnect/bin/acwebhelper: error while loading shared libraries: