':param prefix: string for setting keys
:return: dictionary of image pipeline settings'

def _generate_fake_settings(self, prefix=None):

    def random_string():
        return ''.join([chr(random.randint(97, 123)) for _ in range(10)])
    settings = {'IMAGES_EXPIRES': random.randint(100, 1000), 'IMAGES_STORE': self.tempdir, 'IMAGES_RESULT_FIELD': random_string(), 'IMAGES_URLS_FIELD': random_string(), 'IMAGES_MIN_WIDTH': random.randint(1, 1000), 'IMAGES_MIN_HEIGHT': random.randint(1, 1000), 'IMAGES_THUMBS': {'small': (random.randint(1, 1000), random.randint(1, 1000)), 'big': (random.randint(1, 1000), random.randint(1, 1000))}}
    if (not prefix):
        return settings
    return {(((prefix.upper() + '_') + k) if (k != 'IMAGES_STORE') else k): v for (k, v) in settings.items()}
