Alright, guys. I found the solution.
First, delete your current overall image.
On the main menu (left) Go to:
Design > Social Sharing > [ . . . ] (three dots) > Remove
Save
Now go back to to the root of the main menu.
Click on "Asset Library"
Find the image you had previously uploaded, click [ . . . ] and Delete it.
Go back to to the root of the main menu.
Click on "Pages"
When you hover your cursor over the Home page, you will see a cog icon. Click on it.
Go to Social Sharing.
Delete whatever is in there. It will probably not display because you already deleted from the Asset Library.
Now upload your new image.
Send the link to your website to yourself on iMessage just to make sure.
You should be good.
Cheers!