In family albums, it means that each photo is a snapshot of a moment filled with family history, relationships, and emotions. A photo of a family gathering might show the love between family members, the family traditions like the food on the table or the way everyone is dressed. It can also tell about the family's growth over time, as you can compare different photos from different years.
Well, in the context of family albums, 'a photo tells a thousand stories' implies that every photo holds a wealth of memories. A photo of a family vacation might show the places they visited, the activities they did together, and the bonds that were strengthened during that time. It can also give hints about the family's economic situation (the type of accommodation, for example), and the family's values (if they are into adventure or relaxation). Each photo is like a time capsule that can be opened to relive and understand different aspects of family life.