I think I know what you're getting at. It's the lack of thought, the feeling like your image doesn't matter, the idea of not being recorded and therefore not being remembered, the idea that you're not visibly part of the family.
I have a couple with me and newborn ds whilst still in hospital, a few hours after having him. I look knackered but I love the photo because I look happy. It also kind of shows how his birth affected me. There are none at all with me and newborn dd in the hospital - loads of dh with her - and this upsets me, especially because I later developed depression and felt like I hated her - there's nothing to show that, deep down, I did love her and cuddle her and smile at her. I only have the memories of me shouting at her and pushing her away.

Same thing last year on our first ever family holiday. I was merrily taking pictures of the children and of dh and all of them together. He was also taking photos but it wasn't until we got home and compared that I noticed there were none of me. At all (apart from one where my legs were in the way). This really upset me and I told him so. What upset me most was the idea that, if I were to die tomorrow, there'd be next to no photographic evidence of me being with them at all; almost as though I never existed and therefore nothing to remind them of me - nothing for them to look back on fondly and think, "That's me with my mum," if that makes sense?
I now specifically ask him to take photos of me with the dc. Failing that I take selfies or even videos and, as much as I hate my high-pitched voice with my very obvious Barnsley twang, talk to them whilst recording.