- Download this splash.zip file.
- extract the files within it to your Firefox program directory
- edit the splash.ini file (text editor, like Notepad, should work), so the file paths are correct
- change your shortcuts to point to splash.exe
If you want to change the splash screen provided above, replace the splash.bmp file with a BMP file of your choice. Just make sure you rename it to splash.bmp, thus replacing the included file.