Really simple - grab and install the attached .html file, and run it on Chrome 80+ for Android.
When I attach to the 'touchstart' of an IMG element in Chrome for Android, the pinch zoom no longer works.
If you open this in your Chrome browser on Android, it seems pretty easy to reproduce
From the supplied example:
First image - pinch zoom still works
Second image - pinch zoom is flakey (ensure both fingers cover the image, and try pinch in/out)
I've tried all sorts of cancelBubble, preventDefault, capture ... just can't get the pinch to zoom to continue to work like it does when not attached to the touch events
See if you can make it work, and of course, still work fine on all other browsers.