Here's a link to passport info
Special Requirements for Children Under Age 16
When we got our toddler's photos, we had to take a lot of pictures. He didn't want to sit by himself so they tried photos with a sheet over me, but then it looked like a photo with someone with a sheet over them and that's not allowed. Eventually they just gave my husband the camera and we got a decent photo. We'll see how the baby's photos go.
You can make an appt for dealing with the application. That way, ,you don't have to stand in line. Or at least we could at our office. I believe both parents have to be present.