Telling if a photo or a video is "true" is the same as telling if the written text is "true". You can not tell it by analyzing characters / words in a text, or pixels in a video.

You should analyze the subject who is providing that text / video and decide for yourself, whether you trust that subject or not.

E.g. "Elon Musk is 10 feet tall" - are you reading it on an anonymous X account or on a Business Insider social account? An attached photo of Elon Musk being 10 feet tall does not make a difference.