Polish details carousel image loading

[kbrosnan]

Seeing a flash of grey checkerboard before images load. I've not been able to capture it in a screenshot.

iPhone 7.0 ProxEnterprise build 607

[kbrosnan]

https://www.youtube.com/watch?v=AUYRiai8oVA

[mcomella]

We add a placeholder image (grey checkerboard) before we download new images – apparently we need to polish it up (e.g. download images for adjacent cards).

[brampitoyo]

What if we change our loading state image from grey checkerboard to a blurred one, like this? Maybe it’ll help make the card look more finished.

(Image exported at @3x)

[mcomella]

We could also download images in advance so they're available as the user swipes quickly through, or even when the user is offline.