How long does it take to erase porn images in mind?

I would say usually around 30-40 days to become uncommon to see porn images. To erase them completely, I would say about 60 days.
This is just through my own experiences. It differs for a lot of people, depending on how bad the porn addiction was.

 

Totally agree that it varries depending on the exposure level.

For me It also depends on the amount of work i do on my emotional state. I found that I mentally obsess and recall these images more when I want to act out sexually. And mynurge to act out seems to be directly related to self loathing, anxiety, depression, insecurity, and other emotional issues. So the more I uncover this stuff and work through it, the less I need PMO (and recurring images and fantasies) to soothe myself, and I think about them less And less now.

I watched porn religiously for 22 years with 10 of those being really really bad, and the last 2 years I was watching every day for up to 6+ hours. Now at 90+ days sober it’s still with me, but definitely less and I can notice a huge improvement from day 1.

 

That's fantastic how you've overcome such a tough addiction. For me, I used porn for 3 years starting at age 13.
As for you, don't worry that they don't go away even though it's been a while. I don't know if you still have these destructive emotional states (anxiety, depression, etc.), but what's helped me is meditating.
If you're interested, here's an informative video on meditation and its benefits:

 

I don't think I'll ever forget what I saw, but flashbacks were gone pretty quickly.

 

They're in there. If I wanted to recall things from when I was 13 years old, I'm sure I could.

That's part of the challenge here, you get to keep the reminders inside your tidy little skull. Willpower, control, deliberate choices. You make a choice when you dwell on something. Acknowledge it and dismiss it.

 

It's an interesting question for sure. I'll have to remember and come back here after 60 days

 

A few of them may stick around for quite awhile, but don't let that worry you. See what happens when you stop looking at P, is over time they begin to lose that vivid quality and become more vague. They begin to recede into the background noise of your thoughts and you forget they're even there. If one crosses your mind occasionally that's ok, just let it float on past, and it will continue to fade away.