You can only delete photos from your own Album one at a time. You must have that photo displayed in the Gallery - like the one above.
The horizontal, gray line above the CCOR icon only appears when you display a photo. It has the "Delete photo" command near the left side of the line.
Note: the Edit command does not allow you to edit the file itself. It only lets you edit the Title, Author, and Description of the file.
The "X" button hides the horizontal gray line and its commands. To get the line back, click the hammer and wrench icon that appears in its place.