What object does R beg the narrator not to burn in Chapter 12 and what is her reaction?

In Chapter 12, everyone on the island wakes up to find that photographs have been disappeared. When the narrator goes to take her mother's framed photograph from the mantelpiece to destroy it, R tries to stop her. Though he uses all kinds of strategies to show her why she should not burn the photograph, the narrator feels compelled to comply with the disappearances and she no longer feels anything in association with the photograph anyway, since the disappearance had affected her as planned.