If you already have Gimp installed and you want to upgrade, run the below commands first before upgrading.
sudo apt-get remove gimp-plugin-registry
1.Open Terminal.To open terminal click the Dash home from unity launcher.And type terminal in the search field. And click Terminal.
2.Type the below code in terminal and hit enter.
sudo add-apt-repository ppa:otto-kesselgulasch/gimp
3.Type your ubuntu password if needed.
4.Then press enter to continue or ctrl-c to cancel adding the ppa.
5.Type below command and hit enter
sudo apt-get update
6.Then type below command and press enter
sudo apt-get install gimp
Type y and hit enter to confirm GIMP installation.
