A file or photograph permanently deleted from the device is, as the term implies, permanently deleted. As for whether of not a the activity (and files) associated with centrally-managed device are visible to the System Administrator will be determined by the applied management policy.
As management policy and associated systems are unique to the organisation, you’ll need to ask this question of the System Administrator that manages your device.
For “managed” devices, you might be best advised to assume that everything is visible to the Administrators.