Here you will be able to change the stock Shoptimized branding for your own logos and favicon imagery
Here's an interactive tutorial for the visual learners
Use Custom Logo: Keep this selected to use your own custom logo.
Custom Logo: Select the logo image you wish to use in your store. (Be sure to use a transparent PNG for this)
Max Logo Width: Allows you to set the width of your logo. We suggest no greater than 245 pixels wide.
Mobile Logo: Select your mobile-optimized logo for use here. We suggest the following dimensions: 600 pixels wide and 180 pixels high.
Favicon: A favicon is a small 16×16 pixel version of your icon. It’s how a browser displays your logo in the top left corner of a browser. If someone saves your website on their phone, it will also show your logo, so it’s important! Don’t leave this out.