It could be either.

If I am standing in front of the Tower of London and I ask you to please take a picture of me as I don't want to take a selfie, then you would be taking the picture for me.

Alternatively, if you are going on holiday to London and I would like to see what the Tower of London looks like, as I have not seen it before, then I might ask you to please take a picture for me (so that I can see what it looks like when you send the picture on to me).

They are both correct.