The _html routines in Graph::Easy are quite simple. They just wrap some tags around the rendered ascii, boxart, etc. But they do not actually fix problems arising from the discrepancy between source code and rendered html when href's are used as labels. (See my example and patched code, where I use the label string with HTML in it and without, to feed it to Graph::Easy layouting)
I use the outputted graph boxart on a webpage.