How to specify image size in HTML Doxygen?

Apparently, something changed over the years, because in Doxygen 1.8.17 it works almost the way it is described in the original question (no CSS involved):

\image html some.png width=800px

---

Edit: just tried this with Doxygen 1.8.13 and it also works quite well:

\image html some.png width=50%

Put this in the CSS file "Doc/doxygen_html_style.css":

div.image img[src="example.png"]{ 
    width:100px; 
}

And set the Doxygen config variable *HTML_EXTRA_STYLESHEET* to "Doc/doxygen_html_style.css"