HINT: Set both the width_field and height_field attribute to avoid storage IO

[LeoGraciano]

Console INFO:
product.Product.thumbnail: (fields.E101) width_field and height_field attributes are missing
HINT: Set both the width_field and height_field attribute to avoid storage IO

    thumbnail = PictureField(
        _('Thumbnail'),
        upload_to="img/thumbnail",
    )

try save in django admin... img save more, return exception