[learningit]

Seems used code is outdated although it still works.
Should now be done with
.setArt({ 'thumb': iconimage, 'banner' : os.path.join(artfolder,'banner.png'), 'fanart': os.path.join(addonfolder,'fanart.jpg') }) liz.setPath(u)

Code above is sample snippet and needs to be adjusted for use

What is outdated in it? Yes, setArt now provides an alternative way to set item's fanart along with other graphics, but unless there are some serious plans to depreciate setProperty('fanart_image', '/path/to/fanart.jpg') method, using setProperty for fanart is totally legit IMO.

I don't think Martijn was singling out the setProperty call for fanart. According to this: Jarvis_API_changes (wiki) the setting of "thumbnailImage" as a parm on the xbmcgui.ListItem init call is deprecated in Jarvis and setArt() needs to be used instead.