[Feature request] - Zoomed image aligning

[crank-chips]

To make it more like native image viewers in Google Photos and Apple Photos mobile apps there are a few things to improve:

1. Align the zoomed image vertically at the center of the screen until the height of the zoomed image becomes bigger than the height of the screen.
2. Lock the panning gesture to only the X-axis until the height of the zoomed image becomes bigger than the height of the screen.