I've read that the son of Cleopatra was the last Pharaoh, but I've also seen pictures of Roman emperors dressed as Pharaoh. Weren't they "real" Pharaoh?
Could the pictures have been Greek rulers dressed as pharaohs? There was, of course, the Ptolemaic dynasty that ended with Rome's effective conquest of Egypt in the Alexandrine War.
If not, perhaps you heard about this from this article which speculates on Octavian's status as 'pharaoh' by saying:
"Professor Minas-Nerpel believes that it wasn’t Octavian who insisted on having this honour, instead it was Egyptian priests. For 3,000 years there had been an Egyptian pharaoh, they could not simply do away with the position."
In a way, it's kind of a moot point as "pharaoh" was simply the Egyptian word for "king" so whether the average Egyptian saw Romans as the sons of Ra or the chosen of Ptah, they certainly acknowledged them as rulers using the honorific of their native language.
What pictures? Could you show some?