Ability to set background width type not available (All images crop)

[mmasonMHE]

When a background is too large, it simply crops it.

I can not find any ability to set it to anything but width 100%. Being able to set a width/height would be great. But even selecting a css fill type would suffice:

Background fill type: native, fill, contain

I looked at fabric and there are options for changing the backgrounds but nothing exposed.

Love the tool. Thanks.