I haven't created a slideshow in a long time in Photos. So I tried in Sonoma and it creates the slideshow fine, but the images are in random order. I can re-order them when created, and easy if it's 5 pictures, but when it's 25 or more that's really annoying. I did a search and no one has an answer. Seems to work with High Sierra holding down the Control Key, selecting the Folder or Album and it creates it in the order of that folder. So this can't be done in Sonoma?