@ Eric,
You have to change facebook icon path to you own for desktop too via custom CSS.
Go to Appearance -> Theme Option -> Design Option Tab -> Custom CSS paste the following CSS code and Click on save all changes button:
.social-profiles ul li.facebook a {
background-position: 0 0;
background-image: url("images/[email protected]");
background-size: 30px 30px;
}
.social-profiles ul li.facebook a:hover {
background-position: 0 0;
background-image: url("images/[email protected]");
}
Note: Please upload 60px by 60px images for crystal clear view in retina devices.
Thank you.