Deleting a photo by accident feels permanent, but most phones keep a safety net for exactly this situation.

Check the Recently Deleted Folder First

Both iPhone Photos and Google Photos keep a Recently Deleted or Trash album that holds removed images for up to sixty days before permanent deletion. This resolves the vast majority of accidental deletions in under a minute.

When the Trash Folder Is Empty

If the photo is gone from there too, check whether the phone backs up to a cloud service automatically, since a copy may already exist there. As a last resort, data recovery apps can sometimes retrieve files from internal storage, but success drops sharply the longer you keep using the phone after deletion.

The best long-term fix is simply turning on automatic photo backup so this is never a problem again.