Does anyone know how to delete or block(which I thought I had) unsolicited sexually explicit photographic emails popping up in mail boxes, DESPITE, supposedly having a filter to stop these getting through .
Mark as spam. Don't open the mail, just click on the little box next to the title , and then click on Mark as Spam. This will get rid of it and you don't have to see the contents. After a while your server will "get the message" and automatically send this kind of thing to the Spam folder.
Block the sender if your mail server has that option. If you don't know how to block, the best way is to do a Google search on something like " how to block emails on a ( your email server) account". There are instructions for many servers available.