Those are normally the miracolous objects like the picture "Our Lady of the Rosary" in the sanctuary of Pompei
Or they go in the place bounded with the memory of a really existed person like Saint Antonino in Sorrento.
I could not understand this custom, sincerely, but now, when I'm sitting and waiting here, impotently, telling this to you and praying for the good exit of the operation, I would maybe feeling better if I was in such a place, I think.
We often judge what we do not understand -and begin to follow the steps of others when our situation becomes so as the judged persons had before us.
Well, it's time to go for me.I'll pass next 2 days in the hospital, probably.