iOS: improve image gallery loading time

The loading time when the image gallery previews need to be fetched from the server is a lot slower in the iOS app compared to the web app.

In the iOS app, fetching a gallery page of about 30 images takes around 12 seconds. In the web app it’s less than a second (Mobile Safari, same device).

It would be great if the loading time could be improved in the iOS app. It’s quite a slow process trying to find a certain photo by scrolling through the timeline history.