Deleted photos during import

Have you been using Photos or Image Capture to import the photos?

If you have been using Photos, check, if you have opened the correct Photos Library on your Mac.

• Hold down the options key ⌥ while launching Photos.
• When the Library Chooser dialog appears, select each library in turn, if there are several libraries to choose from.

Does one of the libraries hold your Photos?

If not - what happened, after you imported the photos?

Did Photos give you a message that the photos have been imported successfully, or did Photos quit unexpectedly?

Do not restart the Mac, until you found the photos. They may still be in some caches, that would be cleared when you restart the Mac.

With "While launching Photos" I meant "when starting the Photos.app."

Try again:

• Hold down the ⌥ key.
• Keep holding down the ⌥ key while double clicking the Photos.app to start it.
• When the dialog to select a Photos Library appears, select the largest library from the list. Try all in turn, to find your photos.

You'll have to restore your iPhone from the backup you made prior to importing into your Photos library. Then do an import but WITHOUT deleting the photos after import. There are too many reported unsuccessful imports and a successful deletions to relay on it. I never use that feature.

If one wants to delete lots of photos from an iPhone use the Image Capture app. Much safer.

Is this a backup of the library or of just the image files?

How was the backup made? Which app?