IPhoto duration of slides in 15.1

Did you tab the display while the slideshow is playing? The "Options" button should appear the right of the video controls, when you tap the display, while the slideshow is playing. I am seeing it both on my iPhone and the iPad Pro.

The Options will bring up the controls.

On my iPad I tab “option”, then I have yo shift the menu up. The slider for the speed is hidden below the border of the menu. You can only adjust the duration of the complete slideshow, not the duration of individual slides.

Just in case you have been asking about a slideshow on the iPhone or iPad with iOS 15, and are playing a slideshow from an album, tap the slideshow while it is playing, tap "Options", then move the speed slider between the turtle and the rabbit from slow to fast, or vice versa.

I am not sure, what Apple Support has tried, but on my iPad Pro with iPadOS 15.1 it is working exactly as described the iPad User Guide for iPadOS 15. Play videos and slideshows in the Photos app on iPad - Apple Support

When I select an album album in the sidebar and start a slideshow, then:

• To change the slideshow theme, music, and more, tap the screen while the slideshow plays, then tap Options.

This screenshot is from my iPad Pro 11". When I move the slider to the right, the slideshow will play faster.

15.1?

That is not a version of MacOS.

I hope the next system update will fix it for you.

In MacOS it will depend on the slideshow theme. The more elaborate themes are having less options than the themes with only one photo per slide. If you use the Classic theme, you can change the duration of the slideshow by clicking the stop watch icon. To change the duration of selected slides click the checkmark "Theme options" as well.