Here’s what I came up with: First, several of the options use Hammer.js. I decided against having two libraries. PinchZoom.js doesn’t use any CSS, special libraries, etc. Non-minifyed it is 34k. I was having problems getting it to work. iScroll is still out there.
1- The PinchZoom demo works on the github site, but note it is based on version 2.2.0. The demo also has some CSS that corrects a problem in the code. See line 482 of the PinchZoom included file in the upload below for details. In the upload below, the program is corrected (at least for use in the AppStudio demo below - see github issue post noted).
2- The download of the latest release provides 2.3.4. It does not work. It causes a syntax error immediately.
3- If the picture is longer than the viewport height, you will find it is difficult to scroll down to the bottom.
In practice it may be good to add a gutter you can drag.
4- The docs say double tap will zoom in and out - this does not work on any device.
I found that the width settings of the containers are critical and set to 100%. In my case I wanted the image to be close to the width of the device viewport. The image could be longer than the viewport.
Project1.appstudio.zip (252.3 KB)