You'll first need to make the iCloud association with your child's device and turn on photo sharing.
To do that:
Step 1. Link to iCloud
Open the Safe Lagoon app on the iPhone >> enter Safe Lagoon Settings
select link to iCloud - follow the steps and complete using SMS text 2 step verification
Note that our US operations center is in Clifton NJ - so you will see our servers asking for permission to connect to your child's Apple ID
Step 2. Set up photo sharing on the iPhone
Open Settings >> [name at top] >> iCloud >> iCloud Photo Library >> turn on
Step 3. When the iPhone is connected to WiFi photos will automatically upload to Safe Lagoon Gallery.