9:16 vertical aspect ratio not an option?

I'm hoping that there's a simple answer to this. Why isn't 9:16 available for image formats? 16:9 is available..! I want to use photos from my mobile but don't want to crop, or start shooting in 3:4 (which is the only solution I can think of..)

I think the only way is use CSS code, if you share link to page where you want to do this, I can give a code

Thank you both. I just wanted s simple way to use my phone photos within square space (as I've paid for it now) and it looks like there isn't one. But I think that a 2:3 crop sort of works and that's what I can use for now. I can also specify original format in some cases, so there are a few options!