Extension to change GM portrait
I know NOTHING about extensions. I looked at an extension that someone made to change the GM portrait in Dec 2014, and it's not set up to work with the 5E ruleset. Could someone either change that one to work with 5E, or tell me in really simple language what I need to change? I'd like to get my cartoon-DM portrait working again. I know how to insert the portrait into the extension, but I don't know what to change so it is available for 5E.
I'm assuming that making an extension to just use a different GM portrait is easy to set up, of course.