If you want to delete the whole Gallery, what you need to do is:

  • Go to the Galleries for Subscribers section in the left-side menu. 
  • Click the three dots on the right side of the image, and select Delete

If instead what you want to do is delete a single image within a Gallery:

  • Go to the Galleries for Subscribers section in the left-side menu.
  • Click the three dots on the right side of the image and choose Delete.

Keep in mind, this action is irreversible, so proceed only when absolutely certain.