This was mostly just the case in the Akhetaten reign of the Armana period. The images you most likely saw were of Akhetaten and Nefertiti worshiping the Aten, or of the two with their children.

In any case, we don't know for sure why their heads were portrayed as such. Some people believe they were aliens (I personally think that's the biggest piece of shit ever), whereas others believe their heads were binded as childbirth; which I believe to be the proper way of thinking (e.g. logically). Such is the case in many modern African tribes.

So in short, we don't know for sure; but your best bet is to use your head!

Sadly, we know next to nothing of the Armana period... Plus, getting facts that haven't been around for seven thousand years is well.. I don't know if 'impossible' is the word, but anyone who claims to know for sure is either drunk or a liar.

I think the elongated skulls pictured in most Amarna art is mostly just artistic license. Actual examination of the skulls of mummies of the period, including the CT scan recently completed on Tutankhamen, do not show any radically abnormal skulls. Most of the art work shown of Tutankhamen show him to have a slightly elongated skull, but this is not shown in the skull of the mummy. The only person who probably had a mis-shapen skull was Akhenaten himself, and probably his daughters. All of the abnormalities shown in the sculpture, including the pot belly, spindly legs, massive thighs, etc. were just attempts to show the Pharaoh's odd body shape as being the norm.