How to choose file type for Adobe Stock in Illustrator?

Hi guys,

I've gone through Adobe Stock to find some nice assets with a transparent background, and added them all to a Library.

In Illustrator all the thumbnails have a transparent background. Before licensing them I've added a few to my composition and they have a transparent background.

However when I click the shopping cart icon to license them Illustrator downloads the JPEG and not the PNG version.

Where do I find the option to choose PNG?

Thanks!