Answer:
retrieval cues
Explanation:
Retrieval cues: The term retrieval cues are referred to as stimuli that help in memory retrieval, i.e, it helps a person to access long-term memories by bringing them into the person's conscious awareness and also it makes easy for a person to recall a piece of memory in an easier way.
While making a new memory, a person not only makes the memory of the thing but also grasp information about the situation at that point in time because it acts as a trigger to remember the memory again with the help of retrieval cues.
In the question above, The pictures of Grace's wedding served as powerful retrieval cues.