[exaltedwombat]

I'm afraid the fact that your ebooks (and mine), although designed in EPUB will probably have their main distribution in Kindle format has to be a guilty secret. The Sigil community ethos is that Kindle is outside the pale and not to be pandered to.

It's not hard to remove the code between the <SVG> tags and replace it with a simple image. And even if you're staying in EPUB format, check your work on some real-life readers, particularly those common on both flavours of tablet. That's where your book will be read, not in ADE on a computer. And some of them refuse to display images (cover or in body) over a certain file-size. Others display all images at thumbnail size, despite 'correct' EPUB code. They're 'wrong', but the customer is always right...