is it weird to keep couples photos?

it's normal to feel lingering anger and confusion. First, remember that your feelings are valid. It’s okay to feel upset about the photo and other reminders of his ex. Try to see both perspectives; he might have kept the photo for innocent reasons, but your feelings matter too. Reflect on your communication during the argument and think about how you both could have handled it better. Setting boundaries in relationships is important, so it’s okay to express discomfort when things from a partner’s past are too present. focus on your own healing and do things that make you happy.

thank you, that's really nice to hear. I'm thinking of doing online therapy or something because I don't want retroactive jealousy to be a recurring issue in relationships for me, it was really debilitating, and even though I don't love him anymore I still get upset by it. it really wasn't his fault most of the time (although it was my first relationship so maybe he should've known not to give as many details as he did sometimes), but oh well.

It's good to get some perspective and coping skills, especially when you're dealing with stuff like retroactive jealousy. Seriously, your mental health comes first, no matter what. It seems like you're totally embracing this chance to grow, which is amazing. And hey, don't forget, it's totally cool to reach out for support when you need it. Wishing you all the best

I think it is reasonable to retain some memorabilia from previous relationships and that this does not necessarily undermine future relationships

Only If its useful objects like an umbrela, notebook or electronic for example . As for pictures If its there in the PC and he forgot its okay. But If the partner feel uncomfortable I dont see any reason why It shouldnt be deleted, it ust brings problems in the relationship and will make the other wonder of they stilk hold into the past.
Retroactive jealousy is a way more common problem nowadays especially how dating now is easy and people treat others as expendable. People want to feel special and theres nothing wrong with It.

The importance of a current relationship is not undermined by happy memories from former relationships. I still want to keep photo that represent good times in the past, even though I seldom look at them. I would never ask a partner to destroy memorabilia, why should they. It’s how they treat me that matters

If you seldom look at them whats the point? The memories wont go away If you throw the pictures or objects away. It will just probably make the current partner uncomfortable. If they are ok with it good. But If they dont like If should be thrown away. Its an object.
To you it's not important. But its a minor thing to compromise and its a bit ridículous compormising a whole relationship because you cant put away an useless object from an ex. Your life and past wont cease to exist because of the object not being there. It tells that you hold attachment to that person even If you said thats not the case. Because otherwise you would compromise with making the current partner, a human being, feel good by throwing away that object.
If you want to keep remeniscing the past partner you dont need the object to do that. And whats the point of wanting to remember it anyway?
Sure its how they treat me that matters and what makes me feel. If a picture or objects of an ex is more important than shows their priorities

Not everyone, myself included, feels the way you do. It is best not to worry about, lest interfere, with things from the past

If its thats so okay why theres so much posts of people uncomfortable with partners having pictures of ex? This is a common issue in relationhips and Its weird how some people like to get attached to the past or cant compromise simplest things for the partner's emotional well being. Its not about you. Its about how your partner feel. Having It because you forgot and was lazy to throw away is okay. Refusing to delete or throw away objects that have just sentimental value, for the person that is currently by your side to feel safe, that you are supposed to love and put above everything is not okay.

It’s likely because some people are unreasonably possessive and lacking in self confidence which is generally not a good approach

Its not being possessiva and lack self confidence. Its a matter If boundary. I've also seem people calling monogamic people possessive and insecure because they dont like to share partners. It makes no sense and its a shane tactic.
Some people find keep objects and photos of ex disrespectful and of no value and thats It. Then people who cant let the past go act egotistical and start shaming others who have they boundaries straight in this aspect just because they dont put emotional attachment to people they used to ****.

Nothing at all to do with sharing partners