You have been cited under § 4.06 of the Public Courtesy Code: Photographic Blockade
TAKE IT. WE'LL WAIT.
A photograph is being composed across the full width of a public way, and it has now been going on long enough that a small crowd is standing politely out of frame, waiting, aging. Everyone wants you to have the picture. Everyone would also like to keep walking.
This is not a fine. There is no fine. Think about what you did.