When you launch a program like the Mozilla Firefox or the Mozilla Thunderbird, it displays a splash screen with the application logo and the version of the application. If you do not like this splash screen and wish that it looked a different, then you it is time to cheer up because you can easily use your own custom splash screen using an extension called Splash. This same extension works with a number of different applications like Mozilla Firefox, Mozilla Thunderbird, Songbird, Sunbird, and eMusic Remote.
The original Splash extension has been pretty much abandoned by the developer. But someone else has updated the old extension for the new versions of applications. The updated Splash extension starts to work as soon as it is installed. Of course, you will have to restart the application for which it is installed in order to see the splash screen.
In the settings of the Splash extension, you can choose whether to show the splash screen, the background color for the splash screen and the timeout for closing the splash screen. You can also choose an image that is going to be used in the splash screen. Usually the application logo is used, but you can choose any kind of image including a picture of yourself.
Just like the image, you can also add a text line in the splash screen. This text could be anything from your name to your city. For this text, you can choose the font face, font size, color and the font style. Furthermore, you can choose to have a music file (WAV file) to be played when the splash screen is shown.
With all these options, you basically have a very customizable splash screen of your own for Firefox, Thunderbird, Flock, Songbird and some other applications.
You can download & install Splash extension from https://addons.mozilla.org/en-US/firefox/addon/splash-36-update/.