Install Gimp 2.10 Using PPA

The developer Otto Kesselgulasch maintains an unofficial PPA, which has the latest version of the Gimp program for you to install on Ubuntu 17.10 and 18.04 (16.04 builds are said to be on the way), .

$ sudo add-apt-repository ppa:otto-kesselgulasch/gimp
$ sudo apt update
$ sudo apt install gimp

The above PPA will install or upgrade (if you already have GIMP 2.8) to GIMP 2.10.