Nine Rogues - After capturing Luther
 

After I captured Luther and returned to Elizabeth Swann she spoke of finding the nine portraits, etc, etc. but there was no next step to the quest itself, am I missing something?

It is a treasure quest. You will get portraits of the rogues as you eliminate unwanted elements in the game.

Nothing more than that. With each portrait you will get some gold. :icon_chest:

Just another pretty thing to look at on your treasures page in your journal....alas, nothing to do with it..(yet i hope)

How do I get portraits?

Kill enemies, any one of them. They come randomly.