saying 'based on a true story' doesn't make it that credible. i loved the movie, but i could see parts where it was false, for instance witches sacrifice children to gain higher levels in the eyes of the devil, not true. the clapping, the noises, the moving, even the possession i believe, but things like the person being grabbed and thrown around like a rag doll, almost certain it was added to scare people. it's a movie to entertain not educate after all. the Warrens are well known and they do their research [before retirement i mean] but a lot of what made it into the film is their to scare.
Lorraine is claimed to be a clairvoyant and medium so she could see, sense and even channel spirits, but touching a photograph and getting an emotion involving the day its a strong form of empathy [a subject i'm not well versed in] not only has she not claimed to be one, i think it's a far stretch to claim she could sense an emotion off a photograph. [more likely she saw the smiling faces and commented on it] if you mean the scene at the end where she places her head on the wifes head, a heavenly light glows on her, and clips from the previous scene show, i strongly believe was pure fiction. i do think there was a spiritual connection, at the very least Lorraine gave some energy, but i don't think it's possible for a psychic to touch a person and they see visions.
as i said, i really liked the movie, but it was meant to entertain and shock. if it did have a message, it was probably Christianity is good and is the only thing that can protect you. but the warrens were devout Christians, so i give it a pass. if i were you, i wouldn't base my knowledge off movies unless they're documentaries. a documentary doesn't start with 'based on a true story'. they do have books out if you're interested in learning about their experiences.