By default, videos in the Photos app auto-play in several instances on iOS 13, making it a great way to get a quick, extended glimpse when you're browsing. But this isn't always ideal — especially when you're flipping through private or embarrassing videos and other eyes are on your screen. Fortunately, Apple has an easy way to disable this feature.
In iOS 13, Photos is dived into four tabs: Photos, For You, Albums, and Search. The video auto-play feature exists within each of these four tabs, but only in full-screen view and responsive grid view (layout with different sized squares).
Videos may auto-play in the Months view in the Photos tab, but this isn't common. In responsive grid view, videos will only auto-play if they are in the larger squares.
To turn off the auto-playing video feature, launch the Settings app and go into "Photos." Now, scroll down and toggle off "Auto-Play Videos and Live Photos" under the Photos Tab section.
Once it's disabled, videos won't automatically play in full-screen or responsive grid view in any of the four tabs unless you tap on the play button. Below, you can see videos in both views not auto-playing (unless manually played).
You can go back and enable the feature from the same Settings page if you want videos to auto-play again in the Photos app.
Live Photos automatically play for a few seconds in each of the four Photos tabs, but usually only when in full-screen view. They also auto-play under the Months and Days views in the Photos tab, but it doesn't always work (potential bug).
Unfortunately, you can't disable auto-playing for Live Photos in full-screen view, but you can turn it off in the Months and Days views in the Photos tab. To do so, you can toggle off the same setting in the first section (Settings –> Photos –> turn off "Auto-Play Videos and Live Photos"). With the setting disabled, you can see below that Live Photos still auto-play in full-screen view, but not in the Days view.