How to recover deleted photos

As Servant of Cats says, a a great safety feature on the iPhone is that deleted pictures remain in the "Recently Deleted" view for 30 days before they are removed permanently. This safety feature can be defeated, though, by choosing to prematurely delete pictures from the "Recently Deleted" view.  When we select pictures to remove them from "Recently Deleted," we get this warning before the final step:

Which says "This will delete the selected photos from iCloud and all connected devices." We should take this warning seriously.

If you use iCloud Photos, then iCloud "synchronizes" its Photos Library with the phone, so what you see on the phone is what is at iCloud. iCloud Photos doesn't keep pictures in "Recently Deleted" any longer than the phone does. So it's really important to look carefully at the Recently Deleted pictures before deleting them permanently. Unfortunately, there is no 2nd safety feature in case we didn't heed the warning for the first safety.

Some pictures transferred from a computer can be viewed in Photos but they can't be modified by Photos, so there may be some operations that produce a warning about those being at risk. So if you’re missing pictures that were transferred from a computer, then you should look on the computer for the originals.

You can see this:

         https://support.apple.com/en-us/118558

Basically the above says to look in Recently Deleted and in Hidden. Be sure to check your Library thoroughly-- the pictures may not be where you expect, as dates may have changed. You can use the search field with the date or location. And remember, you can sort the Library by date captured or by date added. Also, your Library view now has filters, and you may not have your filter set to "All Items.”

If you don't use iCloud Photos, but you have Settings>Apple ID>iCloud Backup turned on, then you may be able to recover data. You should look here:

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support 

“Restore” is what you do when you buy a new phone, so this safety, if you have it set, requires you to erase everything on your phone and replace it with the backup.

Unfortunately, if you don't keep your own backups to an external drive, then there really isn't any place else to look. You can backup pictures to a computer or just save them to an external drive. You can see this:

Transfer photos and videos from your iPhone or iPad to your Mac or PC

Check the Recently Deleted album. That's your safety net.

If it has been less than 30 days since you deleted your photos, and you have not deleted them from the Recently Deleted album, you should be able to restore them from there.

Go to photos. Then click on collections. Scroll to the bottom and you’ll see an option for deleted photos