Memories is a short, quiet poem about loss. The speaker is looking at photographs of a time spent with someone who is no longer there. We aren't told why. The person could have died, moved away, or the relationship could simply have ended, and the poem leaves that open.
What comes through most clearly is how little the speaker feels they have left. The words "the only things I can hold on to" make the pictures sound like a last, fragile link to the past. The phrase "the way things used to be" suggests that life has changed a great deal, and that the speaker misses not only the person but the whole feeling of those days.
The mood is sad and tender, but not dramatic. The short lines and plain wording slow the poem down, almost like someone pausing over each photo. The final line, "when I was with you," lands softly, and it carries the ache of the poem: that time is over.