Open source this blog — Notionic
First, edit the
Header.js
file and add a line of code at the top of the file (as shown in the image):import Image from 'next/image'

Then scroll down, around line 180 (as shown in the picture), delete the original logo code (the part selected in the picture):

Add your logo code, using the image
favicon.png
(as shown in the image):<Image src='/favicon.png' alt='Logo' width={20} height={20} />

Note the indentation of the code.