It is rather simple to modify these transitions.
To start, you have to install the developer tools. You will find the application, Quartz Composer, at /Developer/Applications/Graphic Tools/Quartz Composer.
The file which manages the transitions of slideshows in Tiger is named SlideshowTransition.qtz. You can find it in /System/Library/PrivateFrameworks/Slideshow.framework/Versions/A/Resources/
If you open it, you will understand how intuitive the program is.
In the same vain, it is possible to make the same change with the application Photo Booth from the latest iMac G5. All you have to do is edit Photo Booth.app/Contents/Resources/Video.qtz
We leave it to the creative to submit their work to us.
