How to get Photos in macOS Sequoia (15.x) to default to Classic theme in the slideshow?

by Rubin|Published January 26, 2026

In Photos in macOS Sequoia (15.x), the Photos app has changed the “Files > Play Slideshow…” selection to jump right into the slideshow without offering the dialog to choose a theme.

I’m not sure what theme it is using, but it displays multiple slides per page.

I want Classic, that just displays one per page. How do I set that default?