More flexibility around size of page cover image

[denisemcg]

I'm using cover images for my main landing pages as it's a great way to add color and make the pages more visually appealing. However, they take up a lot of retail space. As a result, users have to scroll down to see the page contents.

You currently provide two size options: Hero and Full.
I'd like another one (at least). For example, "half height".