Forum inside Android app - cannot access gallery to add pictures to post

We are creating an mobile app which includes our forum, accessed through one of the tabs on the app.

All seems to work fine, but I can’t seem to post a picture. Using a normal browser, pressing this would access the phone’s gallery, but when in the app, nothing happens. This is an Android device.

PS - I’m not the dev, but wondering if someone could give info that I can pass on to him to save his time.

You might want to share the git repo, error logs etc.

Is it a fork/derivative of: GitHub - pmusaraj/discourse-mobile-single-site-app: Single-site app wrapper for a Discourse site. Supports Push Notifications via OneSignal. ?