Editing entire slideshows in Windows Movie Maker?

Hi, when I try to create a slideshow in WMM each image is set by default to play for 5 seconds. I know how to change the duration of individual images but how would I extend EACH picture so that they all show for 6 seconds instead of 5? I would also like to know how to place a transition between ALL the photos so I don't have to go through one by one.