If you take a picture of the Mona Lisa with your own camera. Can you use it as one of your main website images?

I used the Mona Lisa as an example, but that's the kind of thing I'm unsure of.

I have a small sculpture that's quite popular... I'd like to use part of it for my logo but think it's not legal to do so.

So I want to confirm. It may be obvious but I'm unsure so I'll ask anyway...