ダウンロードはここ
https://www.gimp.org/downloads/
今回は、そのままインストールで問題無しでした。
https://www.gimp.org/news/2018/11/08/gimp-2-10-8-released/
This time, it was installed as it was and there was no problem.

良いものには、寄付ですね。
https://www.gimp.org/donating/
For good things, it is a donation.