I certainly relate to this frustration - I swing between feeling glad that old school friends who did similar (sharing underage videos; some groping - basically what you've detailed) don't agonize over their behaviour in the way that I do on a daily basis with my own, to wanting to confront them all over Facebook and real life, to force them to deal with the fact that many of them are technically child abusers and pornographers.
I also wonder why I am unable to 'let go' of my relationship with a 16/ 17-year-old after 5 years when I even know someone who at 25 had a relationship with someone that age. Indeed, my aunt's first husband was 25 to her 15 when they first started dating. One of my dear uni friends started dating her husband when she was 16 and he was 26 and I've never had the heart to tell her how inappropriate I think this is (nor would she listen, of course - as far as I can tell, she's happily married!) I feel a lot of people have either experienced abuse or perpetuated abuse without having labelled it as such.
I find it very sad, frustrating and anger-inducing to think that my utterly lovely girlfriend's rather repellent and abusive ex-boyfriend completely frames their relationship as though he were some poor exploited victim, to the extent that this narrative has been accepted online, despite the fact that he treated her very badly during their relationship. She wouldn't be comfortable with me giving any details, but she definitely had a really hard time of it and it makes me very sad that even an apology or some recognition of his own behaviour would help her heal a lot of wounds and yet he absolutely refuses to see himself as anything but sinned-against.
In fact, I have several female friends who suffered abuse in past relationships and the impression I have of all of these ex-boyfriends is that they view themselves as "nice" guys... the idea that they might be abusers, harassers or rapists, would never even cross their minds, it seems.
The problem is, legal definitions are often shifting and more ad hoc. than they first appear. Academic and medical sources use their own definitions of abuse. Regarding child pornography, TBH I don't know whether your images would count... I think not (or, at least, you wouldn't be prosecuted) but it is hard to say. Try not to worry too much though, if you can.