How can I make my 19-month old granddaughter less shy towards me?

We see the little grands twice a year and the smaller they were the more shy they were when we'd first arrive. But it didn't take long. I made sure they had photos of us between visits. Photos of us with them are really good. Then I send cards and small books about every month so they are reminded who we are in between visits. Phone calls are good tho at that age they don't quite understand who's on the other end. It'll get better with age.