A favicon is the small image associated with a particular website. Most browsers display these as a visual reminder of the website in the address bar or in tabs. By default, the favicon for Course-in-a-Box courses is the box emoji pictured below.
Head to favicon.io, a free and extensive resource that offers tools to quickly generate the correct files using an image, text, or emoji.
Once you’ve generated the favicon you’d like, the website will download a .ZIP folder called favicon_io that contains 6 different images. For Course-in-a-Box purposes, you’ll only need the one titled favicon.ico
As long as your file is named favicon.ico, you don’t need to make any code changes for this one. Head to the img folder,  click Add File > Upload Files (top right above the list of files), and use the upload tool to add your image. Once your file has uploaded, commit your changes and wait a few minutes to see the updated favicon appear.
https://github.com/your-github-username/course-in-a-box/tree/gh-pages/img
You can update the favicon anytime by following this same process. Uploading a file with the same name will overwrite the previous version so you don’t need to worry about deleting old versions.