Random Background Rotation with transition effect

im not exactly sure where to start
right now im using a script for dhtml to rotate imaged randomly
what i hope to accomplish is background , that will have some type of transition effect and randomly show my images

i have 32 images atm i would like to rotate through

i found this and have tried to use it , but not exactly what i want , i need a transitional effect of somekind, and want it to rotate at a given amount of time , say maybe 12seconds
http://www.kirupa.com/developer/mx/loadingrandombackground2.htm

Thank you for all your help