Never mind how I know, I just know this works.
First you better edit all those forum posts, you won't be able to get to them afterwards
If you want the pics really gone you have to get rid of them where you hosted them, if you delete them from your posts they'll still be there if someone 'quoted' the post with them in it.
to remove your account you must to log in to your profile at members.Literotica.com and create a story titled "REMOVE". In the body of the story, request that your membership be terminated.
Account cancellations are usually done within 4-7 days.