The Secret World of Lewis Carroll
The “disturbing images” in question are photos taken by Lewis Carroll. Click  to see them in book format.
The Secret World of Lewis Carroll uncovered a photo of Lorina Liddell in the archives of the Musée Cantini.
As you can see above, the photo in the BBC programme only uses the top half of Lorina.
Click here for the whole picture.
The photo sheds new light on the “was Lewis Carroll a pedophile” question.