Firefox fails to render SVG at image shape

[r3code]

During work at #105 I noticed that Firefox couldn't process SVG from external file but Chrome works fine.
What you see in Chrome (all OK)

What you see in Firefox 68 (SVG dimensions detected wrong)

This is due to longterm Firefox SVG drawing bug.

The workaround

Edit SVG source, add to root <svg> element width and height attributes (see https://stackoverflow.com/a/28692538/469898)

[r3code]

Let's call Image - the Image Shape, Picture - the image drawn inside the Image Shape.
I think there should be a fallback option for such cases something like fallbackPictureSize if it possible.