When exporting any Group into SVG, I see some illegal characters in the base64 string " ". Base64 decoding fails. These are the line break points of the PNG image.
xlink:href="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAbUlEQVR42mOMi4v7 z0AmaG9vZ2ABMRYuXEiy5h07djBISUlBDACBZ8+ekWTA8uXLGTw8PBiYGCgEw8AA FnQBaWlpvBqePn1KmQtAUYfXBSAb0BWR5AVS08RwiUZQxgClbbIMAGVJUKiDMgY5 AAAckR2JbOwokAAAAABJRU5ErkJggg=="