Run the following commands to clear out the package cache, resolve dependencies, and (hopefully) fix install issues:
sudo apt update
sudo apt -f install
sudo apt full-upgrade
sudo apt install gimp
Breaking this down a bit more:
sudo apt update
This command will download new package caches and package data from the Ubuntu servers.
sudo apt -f install
This command, known as "fix all the problems" will attempt to smartly resolve any dependency issues, and re-install any broken packages. In your case, it will likely re-install the missing GEGL library.
sudo apt full-upgrade
This command runs a full upgrade of all of your software to bring you up to the latest version. Note that it does not change your OS version, so it won't upgrade 14.04 to 16.04.
sudo apt install gimp
This command installs gimp
, as one can guess.
aptitude
, it's smarter thanapt-get
and will help with dependencies. See https://askubuntu.com/questions/1244851/ubuntu-20-04-error-on-install-gimp-depends-libgimp2-0-2-10-18-but-it-is/1244864#1244864 – Ollie May 30 '20 at 17:25