You can add up to 5 pictures per icon. To do this first click on the icon you want to add photos to. Select the Camera icon in the pop up. At the bottom of your screen you will see a white dashed square with a plus sign. Click on the square and find the photo you want to add by browsing your computer's files. To delete a photo from a point simply click on the circle X in the top right of the photo.
See video below for visual example.