The English sentence was "are you taking my picture", so I wrote: אתה לוקח את התמונה שלי.
This sentence should be "Are you taking a picture of me?"
To "take a picture" is idiomatic in English. I wouldn't transcribe it literally word-for-word into Hebrew — or into any other language, for that matter.
I would interpret אתה לוקח את התמונה שלי as someone grasping the picture of me out of a heap of photographs.
I agree that "are you taking my picture?" is ambiguous, but one of its meanings is synonymous with "are you taking a picture of me?"
With that said, I think a more exact/literal translation would be: Are you photographing me?
לצלם means to photograph.