Make a graceful warning when encountering non-image file in input folder

[roperi]

If the script encounters a non-image file it fails with the following warning:

Processing:  50% 1/2 [00:03<00:03,  3.72s/it]/usr/local/lib/python3.10/dist-packages/face_crop_plus/utils.py:264: UserWarning: Could not read the image input/.ipynb_checkpoints
  warnings.warn(f"Could not read the image {path}")
Processing:  50% 1/2 [00:03<00:03,  3.72s/it]
Traceback (most recent call last):
  File "/usr/local/bin/face-crop-plus", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.10/dist-packages/face_crop_plus/__main__.py", line 278, in main
    cropper.process_dir(input_dir, output_dir)
  File "/usr/local/lib/python3.10/dist-packages/face_crop_plus/cropper.py", line 909, in process_dir
    list(imap)
  File "/usr/local/lib/python3.10/dist-packages/tqdm/std.py", line 1182, in __iter__
    for obj in iterable:
  File "/usr/lib/python3.10/multiprocessing/pool.py", line 873, in next
    raise value
  File "/usr/lib/python3.10/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/usr/local/lib/python3.10/dist-packages/face_crop_plus/cropper.py", line 817, in process_batch
    images, _, paddings = as_batch(images, self.resize_size)
  File "/usr/local/lib/python3.10/dist-packages/face_crop_plus/utils.py", line 342, in as_batch
    return np.stack(img_batch), np.stack(unscales), np.stack(paddings)
  File "<__array_function__ internals>", line 180, in stack
  File "/usr/local/lib/python3.10/dist-packages/numpy/core/shape_base.py", line 422, in stack
    raise ValueError('need at least one array to stack')
ValueError: need at least one array to stack

First time I saw it i thought no image in the input folder was cropped.

EDIT: I know one should put images in the input folder but sometimes some hidden files are created as it happens when running script from a Google's Colab (as seen in example above).

[mantasu]

True, especially with Macs always putting their invisible .DS_Store