IPhone :: High-Res Pictures Resized In Low-Res Automatically

In the past, before iOS4, I was able to assign hi - res picture to my contacts.When someone called, the large picture would show up,not the little pic in the top right corner of the screen.Yes,I am using the Google sync/exchange.But I also know that assigning a picture to a contact on the iPhone will use that picture and it will be hi - res.Now,after iOS4,its 50 - 50.I've assigned a picture to my wife. And the picture is hi - res.When she calls I get the large picture.But assigning a picture to my son, its resized so when he calls I only get the small picture and is a low - res version of what I assigned.I haven't changed any settings in Google either.So what might make some pictures show up correctly, and others not?Any ideas or anyone else experiencing this as well?