Faster image scrolling and fix zoom out issue

[rodepanda7]

Closes #458

Summary

Previously, you could zoom out on a photo in an album and it would stay zoomed out.
Furthermore, photos are not cached correctly, so when you open a photo and scroll to the next one, the loading time is annoyingly long.

How to test

Steps to test the changes you made:

1. Go to an album with a couple of photos so you can scroll a couple of times
2. Click on an image (I'd do the first one so you can scroll more)
3. Scroll a couple of times and the loading time will be a lot smaller. You can also zoom out and the photo will go back to the original size instead of a zoomed-out size.

[JAicewizard]

Hey thanks for the PR! I will be there next week again, but thanks for starting with helping the app :)