I think because the Mona Lisa is such an iconic painting and is so well-known that everybody knows of the painting and go to the Louvre to see the painting when it comes to there being remakes and parodies of it everyone will know the painting and straight away know that it’s the Mona Lisa so for there to be remakes and parodies of the painting everyone will find them funny and maybe even make there own as the understand the joke behind the picture and what it’s meant to be.
There are so many parodies of the Mona Lisa now that I wasn’t sure which ones to show but I found this website that has three pages of different parodies. Some are very well done and others you can tell are people joking around using online websites, for example FACEinHOLE (http://www.faceinhole.com) where you can edit you face, or whichever face you like into a variety of different photos.
If you were to search ‘Mona Lisa’ into FACEinHOLE you can see various choices of Mona Lisa style photos which you can edit your face onto. source: http://www.faceinhole.com/us/search-results/?SearchCriteria=mona+lisa
I think with it being so easy to make Mona Lisa parodies everyone is doing it and the editing of Mona Lisa is just fun and games like parodies are meant to be, but when there’s parodies of Osama Bin Laden’s and Adolf Hitler’s face on the Mona Lisa I think the joke could be taken differently by people that may not take that as a joke, so these parodies could also end up being quite controversial.