To embed a presentation select Slides from the Google Embeds section of the Insert menu. After inserting a presentation click the settings (gear) icon to use the auto start, loop playback and delay time options.

You should publish the presentation so that it will appear for everyone.

Note: on a mobile device the slideshow doesn't start until the viewer clicks on it to open it. When you click on it the slides show up vertically rather than as a slideshow.

Field Day 2

See also the Photo Gallery From Drive page