Looking, what is proper..?  Well, I don't claim to be an authority and I know there are many shades of opinion on this...so anything I say will likely be rebuked by someone.
Regarding looking a t cleavage, we understand that is sort of subjective.  Some of the lovely young tellers at my bank sometimes display quite a bit of cleavage, which most guys would find attractive.  But if I'm standing there where I can look down at her cleavage while she's counting my money,  is it wrong to sneak a peak?  And if she glances up and catches me, should I be embarrassed?
But as far as  my taking a photo, without her permission, that would be utterly disgusting whether "legal" or not.  We can agree on that, right?
And for a cop t do that to a fellow officer then carry the photo around on his phone is unprofessional to say the least.  Yet I have a question-- do policewoman officers really show that much cleavage in uniforms? And  how did he take that photo without her knowing?