There aren't many pictures with me with dc when they were newborn. You'd think they'd arrived on the bus considering the absence of anyone looking like their mummy in any of the photos.
I regret it hugely. There are photos of them with every Tom Dick and Harry though. I push myself into photos much more nowadays, but I feel v sad I'm not in more of them when they were babies.
To OP If there were picture of you but you are being edited out in favour of Sil then yes I'd be pretty upset too. Maybe it is being too sensitive, but hey that's the kind of thing I (and you too it seems) get sensitive about.
Mind you my mil has a talent for being incredibly insensitive too. She means well though That's the mantra I keep telling myself anyway
Make sure you put lots of photos around your own home with you in them!