In Firefox 28 roll over any link with an image, see
Unexpected value 200 parsing viewBox attribute.
in Browser console/Firebug. In Chromium developer console see
Warning: Problem parsing viewBox="200"
The logic in line 169 is faulty. As a result the viewBox is set to 200 (if the image is wide not tall) instead of a string of four numbers like "0 0 300 200", and the former is invalid SVG.