Rogues' Gallery Meaning

(idiomatic, by extension) A group of lawbreakers or other disreputable characters.

Example: A set of pictures of convicted or suspected criminals used in law enforcement investigations to help witnesses identify suspects.
1866, "Readings for the Young: The Rogues' Gallery," in The Christian Treasury, Johnstone, Hunter & Co. (Edinburgh), pp. 322-323:
  When the policemen arrest a man . . . if there is good reason to suspect him, they take his picture before they let him go. . . . Then they put the picture up in the rogues' gallery among the others, where everybody who comes there can see it.
1984, William Diehl, Hooligans, ISBN 9780345312013, p. 41
  "Recognize these people?" Dutch asked, pointing to the rogues' gallery.
  I nodded. "All of 'em. Cutthroats to the man."
1997, Rohinton Mistry, Such a Long Journey, ISBN 9780771060571, p. 325:
  The old staple of every demonstration: gully gully may shor hai, Congress Party chor hai—the cry goes up in every alley, Congress Party is a 'rogues' gallery—was very much in evidence.
2006, "The Man Who Sold the Bomb," Time, 6 Feb.:
  For more than a decade, Khan, the father of Pakistan's nuclear bomb, masterminded a vast, clandestine and hugely profitable enterprise whose mission boiled down to this: selling to a rogues' gallery of nations the technology and equipment to make nuclear weapons.