New version of <https://brionv.com/misc/commons-mockup/> mosaic layout concept, now with selectable simulated devices at phone and tablet sizes.

Photos are oriented along the 'long' side of the screen, with even column(s) and scrolling along that direction -- vertical for portrait, horizontal for landscape. That's one column for phones, two for 7-inch Android tablets, and 3 for other tablets. Photos that would be "longer" than the screen are shrunk down a bit and centered in the column; this keeps extreme panoramas and such from going too crazy, but doesn't break up the mosaic flow the rest of the time.

In RTL, the horizontal layout/scrolling could be flipped, but I haven't mocked that.

The small green numbers are sequence numbers and are just there to get a feel for the layout's order. They wouldn't be shown 'for real'.

Questions:

* Is this generally good? Should we continue to pursue this design?

* This mosaic layout attempts to put chronologically adjacent items near each other across the columns, but things don't always scan in order because there aren't even rows that cut across the columns. If this is too confusing, we could switch to a Google Image Search style mosaic for tablet view, where we have even rows instead of columns. This would be inconsistent with the phone view, then.

* Any feedback on the detail page? Should everything be overlaid or should there be a drawer, or a swipe, or?

-- brion