Click , click the down arrow next to Music Library, then select a song or songs.
Choose Theme Songs from the pop-up menu to see music included with Photos, or choose Music to see music from your library. Drag the songs you selected to change the order they play in. To delete a song, select it and press Delete.
Note: If you don’t see music from your music library listed, quit Photos, then open Music and sign in. With Music open, open Photos again, then select your slideshow. Click .
To stop playing a slideshow, press the Esc (Escape) key. Press the arrow keys to skip forward or back through the slides, and press the Space bar to pause the slideshow.
Note: Slideshows appear under Projects in the sidebar. If you use iCloud Shared Photo Library, you must choose Both Libraries from the Library pop-up menu in the toolbar to see projects you’ve created.
Do any of the following:
Add more photos to a slideshow: In the row of thumbnails at the bottom, click Personalize your memories in Photos on MacCreate and work with albums in Photos on Mac