Explain how the eternal stage of nature and the transient state of human beings are contrasted in the poem "A Photograph."

Shirley Toulson's "A Photograph" is certainly about the transient, or passing, state of human beings. The speaker studies a photograph of her mother who has been dead for a number of years. Looking at the photograph is a way for the speaker, in some sense, to be with her mother again. Looking at a still image, of a moment frozen in time is a way for the speaker to momentarily ameliorate the pain that is a direct result of the fact that human life is transient.
Perhaps the key image in the poem is the image of the sea washing her mother's "terribly transient feet." The speaker points out that the sea "appears to have changed less" than her mother did. If we interpret the sea here as a symbol of the natural world, this would indeed suggest that nature is, relative to human beings, eternal. When someone we love passes away, it often can seem so strange because the rest of the world seems unaffected. We almost expect the world around us, even the natural world, to show some signs of the pain that we feel. Our world, psychologically and emotionally, has changed so profoundly, but the natural world around us is indifferent and unchanging. This can be an odd, uncomfortable sensation, and this is in part the sensation that the poem captures so well.