Among all the softwares I use, in my opinion The GIMP is the best one. Maybe
even better than Photoshop!!! I love it and I made some splashscreens
for it. Some of them are girl-centric ;-) and some other are made using
some pictures of mine.. Just right-click on the image and select "save image as..." and save them with the name
gimp_splash.png.
How to cusomize your GIMP Splash ImageIt's
easy to make your own splash image for The GIMP. You can use whatever
picture you want, the only requiremtn is to size it to more than
300x200 pixels, otherwise the text will be cut off. These splash images
are made using the Jimmac's 'official' template that can be found
here. Please note that all my splash images are named 01, 02, 03, and so on: you will need to rename them to
gimp_splash.png and cpoy them to the proper folder:
$PREFIX/gimp/2.0/images/gimp_splash.png. From the 2.2 version of The GIMP, it will also be searched in your personal GIMP directory
~/.gimp-2.2/. Have fun!
DO IT WITH WINDOWS!
You can customize your GIMP splash even if you are running The GIMP for Windows!
Just copy
gimp_splash.png into its folder. Note that I'm still on version 2.0 (in the splash image 2.2 is written).
So, for version 2.0 the folder is
C:\Program Files\GIMP-2.0\share\gimp\2.0\images (see picture below).

Windows folder containing gimp-splash.png

The gimp_splash.png showing off while running The GIMP for Windows