I\'m trying to do a signature in HTML using images that are encoded in base 64 data URLs. Here\'s an example:
I’m using embedded SVG, here is why:
But if you really want to display images in Gmail and Outlook, you will need to load these via HTTP.
The guy from CSS-tricks has a nice guide on SVG in email: https://css-tricks.com/a-guide-on-svg-support-in-email/
The final solution is the following:
/* Resize an element that has a width and height of zero to full size */
.showy {
height: 100% !important;
width: 100% !important;
}

But I personally don’t like it, because I don’t want a client to ask the user if he wants to load additional resources.