def is_file_image(filename):
    """Return if a file's extension is an image's.

    Args:
        filename(str): file path.

    Returns:
        (bool): if the file is image or not.

    """
    img_ex = ['jpg', 'png', 'bmp', 'jpeg', 'tiff']
    if '.' not in filename:
        return False
    s = filename.split('.')

    if s[-1].lower() not in img_ex:
        return False

    if filename.startswith('.'):
        return False

    return True