With Random Image for SharePoint, you can select multiple images to display randomly when the web part loads. For example, you can add 10 images to the web part and each time you refresh or load the page one of those images will be displayed randomly.
The Random Image Web Part is written in VS 2005 for MOSS 2007. The web part is easy to setup, you simply setup a collection of images and add an image web part to the page. You can then use SharePoints 'Connections' functionality to have the image web part randomly choose from your image library.