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