How to install and configure gimp to your laptop using the command line for Linux Mint or Ubuntu.

sudo apt-get install gimp

Go to Menu->Terminal. And type the above code in terminal and hit enter.

Type your linux mint password and press enter.

Type y and hit enter to confirm gimp installation.

After the successful installation , open Menu → Graphics → Gimp Image Editor is ready to go.

After your successful installation of gimp in your computer;

if you type again the same command to the terminal, you will 

get the above prompt.
Another way to install gimp is using the graphical mode.

Go to Software Manager → and in the search bar, look for Gimp

Image Editor or simply gimp. And hit enter. You will be 

prompted to install the gimp, just click install.