Short-circuit error handling

                margin_size=margin_size

            )

        if not processed.images:

            # It broke, no further handling needed.

            return processed

        z_count = len(zs)

        if not include_lone_images:

            # Don't need sub-images anymore, drop from list:

            processed.images = processed.images[:z_count+1]

        if opts.grid_save and processed.images:

        if opts.grid_save:

            # Auto-save main and sub-grids:

            grid_count = z_count + 1 if z_count > 1 else 1

            for g in range(grid_count):