It seems like to see the diagram you need to import diagram to guvnor defaultPackage. The console only gets images from the defaultPackage (https://issues.jboss.org/browse/JBPM-3277).
name must concatinate ProcessID with "-image.png".
I still have not found my when i try to print i get error and what processEnginePlugin is missing if that is important or not and how to fix it.