No one knows for sure whether this hero story is true or not. The little girl in this photograph (published in stereograph sets) was drowning in the floodwaters when her family's dog swam to her and towed her to safety.
Based on what you know about the Flood, dogs, and the relationship of dogs to their families, what about this story is likely true? What seems unlikely? What questions would it be good it answer?
Even though it is impossible for us to go back and interview this family, the photograph has clues in it that can help us decide the truth of this story. The photo doesn't help us know if the dog WOULD have rescued the little girl -- dogs definitely have a reputation of rescuing people, especially family members -- but it can help us know if the dog COULD swim well enough to rescue her.