Grew into a photograph? (9)

I believe the answer is:

developed

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'grew' is the definition.
('develop' can be a synonym of 'grow')

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for developed that I've seen before include "complex perhaps" , "Like film suitable for viewing" , "mature" , "Caught" , "Grew, progressed, evolved" .)

I've seen this clue in The Mirror.

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