Change arrangement of pictures in a slideshow

First-- don't use File>Play Slideshow. This is a simple slideshow that has no ability to control the presentation.

Instead, use File>Create>Slideshow>Photos. This creates a Project, and you get lots of control. You can add titles, change times and transitions, and all that kind of stuff.

Check out all these adjustments!

See this:

Create slideshows in Photos on Mac - Apple Support

rosefromorchard park wrote:

slideshow. how can you change the arrangement of pictures

With the slideshow playing, tap the icon with six rectangles at the bottom right of the screen. From here, press and hold, then drag your finger around to change where it appears in the slideshow, or keep holding down and choose 'Hide from Memory' to remove it from the slideshow.