If you emptied the recently deleted album, your photos have been deleted from your iPhone completely to free up the storage. However, if your photos have been deleted over 30 days, they will be deleted forever.
To recover your deleted immediately photos from your iPhone, here are some methods for you to try.
Method 1: Recover from iCloud. If you have any backup in your iCloud, you can go to Settings > General > Transfer or Reset iPhone. Click Erase All Content and Setting and type in your Apple ID and password. During the resetting process, choose Restore from iCloud Backup and then choose the latest backup from the list. Wait for the process to finish, and then your photos may be recovered.
Method 2: Recover from iTunes. If you have a Mac running macOS Catalina before and you have backed up your iPhone in iTunes, you can use this way to recover your photos. Connect your iPhone to your Mac and open iTunes. Select your iPhone and go to the General tab, then choose Restore Backup.
No matter which methods you choose to recover your photos, make sure you have backed up your iPhone and your photos have not been deleted over 30 days.