def image_optimizer(data):
    """Optimize an image that has not been saved to a file."""

    if not data:
        return data

    extension = data.name.split('.')[-1]

    extension = (
        extension.upper()
        if extension.lower() != 'jpg' else 'JPEG'
    )

    if config.TINYPNG_KEY:
        tinify.key = config.TINYPNG_KEY
        buffer = tinify.from_buffer(data.file.read()).to_buffer()
    else:
        image = Image.open(data)
        bytes_io = BytesIO()
        image.save(bytes_io, format=extension, optimize=True)
        buffer = bytes_io.getvalue()
    data.seek(0)
    data.file.write(buffer)
    data.file.truncate()
    return data


class OptimizedImageField(ImageField):
    """An ImageField that gets optimized on save() using tinyPNG."""

    def save_form_data(self, instance, data):
        """Remove the OptimizedNotOptimized object on clearing the image."""
        # Are we updating an image?
        updating_image = True if data and getattr(instance, self.name) != data else False

        if updating_image:
            data = image_optimizer(data)
        super().save_form_data(instance, data)