The instructions @ericklan posted are on the right track, though they aren't quite clear to me and seem to recommend more than is necessary....
It sounds like you don't have the GD extension installed. I don't use Ubuntu any longer, but I think it may be named php5-gd,...
How To Install Linux, Apache, MySQL, PHP on Ubuntu: Set Up The steps in this tutorial require the user to have root privileges on your...
How To Install Webmin on Debian 10 Installing Webmin sudo nano /etc/apt/sources.list Then add this line to the bottom of the file to add the new repository: deb...
Grub Customizer is a great application, it allows you to add or edit menu entry and change the default OS boot with GUI....