Open the Photos app
Tap Albums
Scroll down and tap Recently Deleted
Select the photos you want to recover
Tap Recover
Confirm Recover Photo
Check the Hidden album if the photos are not in Recently Deleted
Restore from an iCloud backup if the photos were deleted long ago
Restore from a computer backup if you previously backed up your iPhone
Use the Photos app on Mac or iCloud.com to check for synced photos
Check third-party cloud apps like Google Photos, OneDrive, or Dropbox
Contact Apple Support if the photos are still missing