No, there aren't any.

There is a pic of the helmet by itself in Armageddon, but that pic is a lie 'cause it shows his horns too, as if they're attached to the helm.

Meanwhile Sindel's MKD ending shows Onaga's grave, and you can see his skull inside the coffin, without any armor on, with horns.

He's probably just bald.

Well...not totally bald. He has a Goro ponytail.

I was just kidding. And really?? I feel kind of dumb for not noticing if he does.

Yeah, there's so much shit on his head that most people never notice, but he does in fact have a ponytail of black hair sticking out of the top of his helmet.

Daaaaaamn! I never noticed it either. It's so silly, now I respect him even less than before.

Onaga has hair? Wow can't believe I never noticed that before lol

lols

i pretty much imagine him bald with his ponytail and horns though the helmet suits him because he doesnt look as threatening without it i would probably be laughing whenever i see him

Onaga probably goes to a Kuatan barber; that's how the prince has it, too.