http://www.out-law.com/page-9566 'Out Law' reports that Friday was Ban Bullying at Work Day. This is despite the fact that there isn't specific bullying laws, although in a lot of cases discrimination can be brought into the fold. A recent case involving photoshopping of a Taliban photo to include an employee went down like a lead balloon: http://www.telegraph.co.uk/news/newstopics/howaboutthat/3396950/Asian-employee-superimposed-on-to-bin-Laden-cave-picture-sues-company.html
It seems to me that in the above case anyway the racial slurs that were made are rather more pertinent than the photo that could be considered as office banter.
Readers will be pleased to know that the IP Freely office is a bullying zone, all staff are encouraged to bully each other (all in the interests off research of course).