Icon from Mac OS X Server


I saw the pictures icons (jpeg files or gif files) for Mac OS X server and I would like to get them for my Mac OS X 10.0.3. For instance, I'd like to get the .gif icon that is in the dock on the screenshot here.
If anybody can help ...
In fact, I managed to change the default icon for the jpeg, tiff and gif files. I just had to change the .icns files in the Preview.app application.