I'm sorry about the loss of your belongings.
Holidays after a loss (a loved one, one's health, treasured family belongings) can be difficult. Of course, some losses are far more tragic than others, but still, if you've lost all your household belongings and family memorabilia, or if this is your first holiday season after starting chemotherapy or knowing that your diagnosis is life-threatening, or if this will be the first holiday table without that precious person sitting at it, it's a loss nonetheless.
So my suggestion is to give yourself some time to cry. Take a long shower and let the tears flow. (Long hot showers are the best crying places). Acknowledge the loss, seek forgiveness for those who caused it, and let yourself grieve in a healthy way.
Then try and look around you, and name just one thing you're thankful for. There's an old saying: "it's better to act your way into a new kind of thinking, than to think your way into a new kind of acting". In other words, don't wait until your frustration and sadness and anger have disappeared to start enjoying your family. Take action. The horrible people who stole your pictures don't have your family to make any new memories with. You do. So do one thing. Bake a pie that smells amazing. Or go to a store and buy one new ornament. Or buy a candle with your favorite holiday scent and light it. Don't do everything at once. Take one step at a time towards a new direction.
Your kids will learn from how you respond to this. You can teach them resilience, thankfulness, forgiveness, and how to find joy in the darkest circumstances, or you can teach them that a loss can defeat us. Be honest with them. Tell them you're sad about the loss, just as if you'd tell them you miss Great-Grandma after she passed away. But I imagine if this was Great-Grandma that you were missing, you'd smile as you remembered her favorite ginger cookies, or the way she'd knit mittens every year that were always too small for everyone. And you'd cry, and then you'd dry your tears, and maybe you'd make ginger cookies.