How to change my Outlet Shop profile picture?

Go to the Outlet Shops section.

Here click on the lower top navigation on My Store Account and below on My Outlets.

Then you will see your outlets, and here click next to your outlet on Dashboard.

Now you will see on the left navigation many tools to edit your shop and to add more info.

Click on Profile Picture and here you can delete or add a new profile picture.
And you can also set and change a thumbnail.