Automatically size images based on their aspect ratios

[davidpmccormick]

For #10865

Who is this for?

Everyone

What is it doing for them?

Making images take varying amounts of horizontal space based on their aspect ratios

Landscape images can take up a maximum of 12 columns Square images can take up a maximum of 10 columns Portrait images can take up a maximum of 8 columns

Note: images will continue to be constrained by their height to ensure that they always fit within the viewport, so they may not get to their maximum possible width depending on the user's browser.