Maintain order of images in a Photos Project

Photos is changing the order of the photos to fill the templates. The only slideshow themes, that are letting us arrange the photos freely are the themes with only one photo on each slide. Try the slideshow themes Classic and Ken Burns, if you need a special sequence of your photos to tell a story.

Alternatives to Photos' slideshow include:

iMovie is on every Mac sold.

Others, in order of price:

PhotoToMovie  $49.95

PhotoStage   $60/$80 (depending on the version you prefer)

FotoMagico $99 

Final Cut Pro X $299

It's difficult to compare these apps. They have differences in capability - some are driven off templates. some aren't. Some have a wider variety of transitions. Others will have excellent audio controls. It's worth checking them out to see what meets your needs. However, there is no doubt that Final Cut Pro X is the most capable app of them all. You get what you pay for.  

How are you adding the images from the shared album to the slideshow? Have the photos been shared from your own library and are also in All Photos?

When I create a slideshow project from the photos in a shared album, using the Classic theme, the sequence of the photos in the slideshow project remains the same, when I quit Photos open it again later. But all photos have been shred from my own library.

I cannot test this, as I do not have shared albums with contributions from several people. My shared albums are holding only photos shared from my library, so the are in my library as well as in the shared album.

It might be saver to import the photos contributed by others from your shared album to your Mac by collecting all photos you want to use in a new standard album (File > New Album). This way, the photo will not be removed from your slideshow, if the owner removes it from the shared album.

The problem is, that any text you add to a slideshow will go to a title slide, not to the photo on the slide. If a photo gets removed, the titles may shift.