The act of helping someone's memory of a thing, event or an action by sending them a photo, picture or video of it.
Could be an event, a thing or an action caught on film that someone doesn't remember or "says" they don't remember (a.k.a. plausible deniability or just denial)
I can't believe you don't remember what you did last night, let me send you a video reminder.
Did you say you never wore those hideous clothes, I'll send you a video reminder of you in them?