This thread has made me quite sad. I am sad for the OP who has to see photos of other people's children and feel she will never see those milestones for herself. My heart goes out to you, OP, I have one DD but after a miscarriage, she never got the sibling she would have loved. To make matters worse, a couple of friends had babies about the time mine should have been born, the first time I gave one a cuddle my heart broke, I should have been cuddling my own. Now I see photos on Facebook of them together and sometimes it's hard wishing my daughter had a sibling to take photos with.
But this is life, there will always be someone who has something you want and you can either feel sorry for yourself (understandable and often unavoidable) or happy for the other person (my personal choice).
I also feel sad that some people think posting first day back at school pics are rubbish or boasting. I live abroad, see friends and family once a year if I am lucky, see other friends who live in other countries even less. We all post photos of our kids / holidays / new house etc etc and we are all happy for each other. I would hate to think any of my friends, some of whom are childless, either by choice or not, thought I was boasting because I posted a pic of my DD on her first day back of school. One does make a joke about it in general, but she loves my DD and loves to see how she has grown (usually do a side by side comparison from her first school photo). I also don't think my child-free friend is boasting when she posts amazing holiday pics. Our lives are just different and we all share our important stuff.
I'm glad I have my happy-for-me friends and not some of you guys.
Off to post cute first day back at school photos...