animeted jpg's... HOW?

[ohad]

This is something that's really bugging me and i don't have a clue what the hell happened here

Iam old school, in "my days" an animated picture was a *.gif extension... some might say that *.png can also be animated (i havent checked that out.. and i dont really care)
what i do know.. or used to know anyway is that a *.JPG can NOT be animated

That being said, i am in a group called GAG in facebook(recommend ) and this picture is puzzling me

http://damnxd.org/files/boom.jpg

Its a jpg picture.. and its animated...
i've downloaded it and saved it as *.jpg and of course its "stuck"
renamed it to *.gif and *.png and its still stuck..

The reason iam asking this is
A.like i said.. its puzzling me and iam feeling old
B.i want to send this picture to my GF on Whatsapp but not as a "still" image

Thx in advance