If you go under "Manage -> Profiles" in the top navigation and then click on your sons name it will load the profile.
Then if you click the "Edit" tab you will see in the top left corner of the profile admin has a "No Photo" box, you can drag and drop an image in there or click on the image and it will prompt you to choose a file for uploading.
Afterward you click the "Save Image" button under the image and your profile picture will be saved to the profile.
Pictures do not print on the "Hard Cards" at this time, only the printed versions from the site.
Please watch the linked video for a step by step tutorial on how to add or edit a picture in your profile.