Pictures, videos, and audio recordings should be allowed as evidence in court cases, especially in abuse-related cases. Some states currently do not allow these as evidence if the accused party doesn't know they're being recorded.
Abusive relationships can be quite complicated. It is sometimes difficult to obtain evidence of abuse, especially verbal, emotional, and/or psychological abuse. The abuser often tends to act loving in public and in recordings. This makes it difficult to obtain evidence because of the staged nature of the recordings.
If all relevant recordings of the abuser are allowed as evidence, it will allow the victim to gather and report the abuse much more easily. This will undoubtedly reduce the amount of abuse in the U.S significantly.