The first stanza refers to the childhood days of Poet’s mother when she was twelve years old or so.
The stanza portrays a photograph of her mother when she went for a beach holiday with her cousins and uncle.
The second stanza reveals the poet’s childhood days when her mother became an adult.
It portrays her mother recalling her childhood days while looking at the old photograph of hers.
The third stanza, the poet’s adult life is described in which her mother is not with her anymore.
She has been dead portrays the poet’s looking and the same photograph and recollecting her mother puts her recollecting grief.
She has no words to describe the terrible pain of her mother’s death.
Final Answer:- All above the three phases of the poet’s mother describe childhood to ultimately her death. All the three phases of childhood, motherhood and death are all the phases poet’s describe in the poem “A Photograph”.