HTML and the <img> tag

When you process a docbook formatted document into HTML, <imagedata> tags are transformed into <img> tags by default. Unfortunately the HTML specification does not support SVG content in <img> tags and thus browsers render an error instead of the svg graphic.

As explained in SVG images, adding the attribute format="SVG" in the docbook <imagedata> tag solves the problem. It instructs to use a generic HTML <object> tag instead of <img>.