Customize Splash-Screen
When you start GIMP, you see the splash-screen displaying short status messages while the program is loading all its components.

Installing:

Copy "/home/user_name/.config/GIMP/2.10/splashes" or
Copy "/home/user_name/.var/app/org.gimp.GIMP/config/GIMP/2.10/splashes" <- Folder flatpak

If you don't have the "splashes" folder just create and copy the file you downloaded to this folder.