Base64 image in signature no longer working

I have a base64 logo image in my signature which used to work fine in eM version 7, but now in version 8 it does not work at all. The image simply does not appear. No idea why this functionality would have changed… HTML is HTML, right? Did I miss a setting somewhere?

Note: in order to get HTML (with the base64 logo image) into my signature, I have to put the HTML code into an empty signature.html file, open it in a browser, and then copy/paste the result into the eM signature setup window. In previous versions of eM, the image worked perfectly with this method.

Related feature request: please allow the signature editor to accept raw HTML code.