Open the Photos app
Tap Albums
Scroll down and tap Recently Deleted
Use Face ID, Touch ID, or your passcode if prompted
Select the deleted photos you want to view
Tap a photo to open it full screen
If needed, tap Recover to restore the photo to your library
Check iCloud Photos if the pictures are not in Recently Deleted
Open iCloud.com and sign in with your Apple ID
Go to Photos and look for the missing pictures
Check other synced devices for the deleted photos
Restore from an iCloud backup if the photos were deleted long ago
Restore from a computer backup if you previously backed up your iPhone to Finder or iTunes