Why do I get very intense, vivid, and sometimes frightening visual images during meditation?

I experience extremely vivid, sometimes bizarre or frightening visual images, like a waking dream, during deep meditation. The intensity is often overwhelming and unnerving. I worry that this visual intensity is a sign of underlying instability. Is this normal, or should I be concerned about the impact on my mental health? My name is Atul, my full details are 2nd February 1997, born in Bangalore at 2:00 PM.