Do I question him or not?

I know I shouldn't have but I checked partners phone this morning and found that he had yet again taken a semi hard dick pic which he hasn't sent to me. This isn't the first time he has done this. I questioned him the last time and he said he was going to send to me, but felt that as things weren't great between us, that he shouldn't do it. I'm going through a tough time, emotionally and mentally plus am going through the menopause. This recent photo was taken a week ago and taken in our bathroom when he got home from work one evening. I know this because I checked the date and time. Why do men take dick pics if they aren't sending it to someone ? Not sent to me so has he sent to someone else? If for his own purpose, why? Does he not get to look at his own penis on a daily basis , probably several times a day. I don't know what to do, do I ask him why? Do I leave it and not mention it and let it boil up inside me and gradually let it ruin our relationship thats already at breaking point? If I mention it I will get shouted at for going down his phone. I know I shouldn't have but he can be quite secretive with his phone , taking to the toilet, bathroom, deleting previous messages to male friends and previously female friends . What has he talked about with these friends that he doesn't want me to see? I don't hide my phone or hide what I am doing or delete messages. He can look at my phone at anytime he likes. This is making me feel ill and not helping my current depression :(

Only you can decide if this is something you want to pursue. Is it a big deal? Or is it something that you can get over?