I've never had a photographic memory. I used to dream in video. Now, I'm not sure I do anymore. My dreams are more narrative dialogue than video. I don't know that I care. I don't need technicolor dreams. What difference does it make?
EMDR is of questionable efficacy. I tried it. It helped me remember some traumatic events in greater detail. I didn't see it necessarily as therapeutic. Those details didn't seem to mean anything to my medical care providers, but a proper analysis of those events would finally lead me to understand
the nature of those events as epileptic in genesis. That ultimately brought me to a thorough understanding of my illness, and appropriate diagnostics and treatment.
I doubt there is a specific treatment for "lost ability to visualize memories and images". Have you had an EEG? Videos and images cause electric waveforms which are detectable by EEG.
If you have an EEG and your images and video are AWOL, maybe a neurologist can give you an answer.