Changing Duration of Multiple Slides

I'm looking to be able to select multiple slides and change their duration from the 2 seconds it imports at to 7 seconds without having to change them individually. Having to do that on a number of images makes the idea of making a slideshow an absolute nightmare.

Overall, I'm looking to make a slideshow with each slide lasting 7 seconds, dip to black transition to each and Auto Pan & Zoom to each.

It's so close to perfect, but the only problem is the duration of the slides.

Is this something I can do or is there another program that might better suit my needs? I've tried Adobe Elements, but that doesn't allow me to quickly add an auto pan and zoom. I have yet to try Premier Pro because I suspected I'd run into the same Elements issue.