iCloud Photo Library allows you to store a copy of all your images in iCloud and access them on all your other devices.
Open Settings, select iCloud and tap Photos. From the top you can enable or disable iCloud Photo Library.
Once enabled it can take some time for images to be uploaded but once they are you can view your picture on other iOS devices, a desktop computer, or even access through icloud.com. On your other iOS devices, ensure you are signed in with the same Apple ID and iCloud Photo Library is enabled.