Help surprising my dad!

So.. My husband, our 3 year old son and I just moved to Texas. Our families are all out in California.

I just found out I am pregnant, and I see the doctor tomorrow. We have told a handful of people, but are waiting to tell parents. My husband's mom, dad and brother are coming to Texas for my husband's law enforcement graduation next week. We are going to tell them by taking a photo with my husband, son and I with our son in a shirt saying something about being a big brother.

Long story short, I don't know how to tell my dad! I don't want to have him be the last to know! We never talk on the phone, so he'd instantly know something is up if I called. Should I send him the picture we take and see if he gets it?