There's only one thing to factor in here - it's her house.
If she wants to put up pics of her wedding day, it's her choice.
If she's isn't over them splitting, it's her thing to deal with in her way.
If she wants to remember happy times (I'm presuming the exes were happy at some stage - they married and had a child), then why not.
I'm amazed at how many people go through life judging other people. Why? What is the point?
I split from my husband nearly 7 years ago. We talked as much of it out as we could foresee before we split. We agreed that we would try to be as amicable as possible and retain a sense of family for our DD.
Why is that weird?
We are now better friends than we were for the last 2-3 years of our marriage. We still have lots of family time together. We try to go on at least one family holiday together per year - even if just a long weekend - with our DD. We both have lots of family pics up in our homes.
Why is that odd?
This has not been easy. It takes lots of effort and 'working at it' like any other relationship. We were the world to each other once. We believed it was forever. We still believe on some level that we are soul mates, as are some of our other friends/family. We had a child together whom we both adore. We make an effort every day to make the dynamic work and be positive. Yes, he pisses me off. Yes he exasperates me. Yes he broke my heard but guess what - we're all human and none of us are perfect.
Movingonup - you seem to have convinced yourself that you are not insecure, negative etc etc and this may be the case. The way you post comments and what you say, however, does not reflect this. And children pick up on everything - it's in their DNA. Their genetic code is there for one thing - survival. and as kids, we do this by appeasing and being adorable to the adults around us. It's biology. Be aware.
And she may be a 'mad' so and so but you don't live in her shoes or walk her path. You knowingly took on a man who was previously married and has a child. Reality check = this always come with baggage - just a fact of life.