Add image as base64 encoded

<img src="data:image/png;base64,___iVBORw0KGgoAAAANSUhEU___">

Get the encoded image

Right Click on image > Inspect Element > Network tab (Select all or Images and Reload if necessary) > Right click the image > Copy Image as Data URI

HTML example

data:text/html;base64,PGh0bWw+PGhlYWQ+PG1ldGEgaHR0cC1lcXVpdj0icmVmcmVzaCIgY29udGVudD0iMDt1cmw9aHR0cDovL2FkeGl0ZS1hZHMuY29tLz9wbGFjZW1lbnQ9NDAzMzc2JnJlZGlyZWN0Ij48L2hlYWQ+PC9odG1sPg==