I can see you crystal clear

Could someone explain to me why in the following sentence the adjective is used instead of the adverb? Is it correct in spoken English?

‘Now I can finally see you crystal clear’( why not crystally clearly?)

Because “crystal” and “clear” goes together. The phrase means “completely clear and bright / completely clean and clear”. My doubt is whether it can be used with people.

I think it’s passable in certain situations, for example when looking at an image (webcam, video, etc.). In this case the meaning is ‘I can see your image crystal clear.’

Thank you, Beeesneees.

PS. Why so many “e’s”? I’m always afraid of leaving out one of them.

If you leave out one, they kick you off the forum.

Instead of “I can see your image crystal clear.”,
can I say, “I can see your image crystal clearly.”
Or “I can see your image clearly.” ?
Please comment.

You can’t say ‘crystal clearly’ for the reason already given about it being a specific set phrase.
You can use ‘I can see your image clearly’, just as you can say ‘I can see you clearly’.