Fixing Facebook Icon

Hi,

I have a wordpress site that works fine. When I post a link to my site on Facebook it shows an image from my site along with the link to the site, as it should.

I then setup a subdomain and put a store up. I use most of the same plugins as I used on the main site, other than the commerce plugins for the store.

My issue is, when I copy and page my websites link into Facebook, instead of showing a colored picture from my site, it simply posts the grey image with the white person. Nothing I change makes it post an image.

Can anyone help?

https://store.pureheavencotons.com/