Landscape and square photos always work best.
Your dimensions are not consistent which is why your pictures are appearing warped. If you have one narrow vertical photo and one long landscape photo that is how you wind up with the gray bars around the photos when you upload them to Etsy.
Check out this article on what to size them for proper display. Once you sort that all out you shouldn't have an issue.
:)
https://www.etsy.com/help/article/208