No, this is a simple enough sentence, so everyone would use proper grammar here. We would say "they LOOKED like a painting". But in talking, not writing... Some people may say this: "The views were so beautiful, that... They look like a painting!" In this case, the sentence is being changed half way through, and this does realistically happen in talking, but if it's put into writing it needs punctuation like I've demonstrated.

Almost. The only real problem I see is that "views" is plural while "painting" is singular. I would either say "the views look like paintings" or "the view looked like a painting" I also might say "looked" instead of "look" but that change is not necessary because the views are still there and they still look that way. Such a simple thought doesn't call for accurate detailed explanation. Fewer words will suffice: "The views were beautiful like a painting." "The views were picture perfect."

This is not quite correct. You could say this instead. The view was so beautiful it was as though a painting had come to life. The views were so beautiful to the point they resembled paintings.