shopkeeper logo unsecure

Hi, i recently installed ssl serficate for my webpage. Page is secure, but i get mixed mode, unsecure items on site.
This is the message i get from firefox.
Loading mixed (insecure) display content “https://www.site.com/wp-content/uploads/2016/12/cropped-logoforslag5.jpg” on a secure page[Learn More].

This is the logo inserted by shopkeeper theme. Is there a reason why the sticky logo is not being secure?
any solution.