Is it possible to use custom images for UML items in plantUML?

plantuml-icon-font-sprites allows using font-awesome icons within plantuml. It's awesome!

From PlantUML's Language Reference Guide

    11.6 Legacy HTML
    Some HTML tags are also working:
    <img:file>  : the file must be accessible by the filesystem
    <img:http://url>   : the URL must be available from the Internet

It appears that it shouldn't be a problem. There is also a PlantUML Word Plug-in, that would possibly enable you to paste images over the default ones otherwise.

The following PlantUML code renders a simple diagram - the referenced images have to be in the proper location...

object "inbound message" as m1
object "XML Splitter" as s1

m1 : <img:MessageIcon.gif>
s1 : <img:SplitterIcon.gif>
m2 : <img:MessageIcon.gif>

m1 -> s1
s1 -> m2