转换为png图片
    :param filename: 图片文件名
    :return:

def convert_other_format(filename, format):
    """
    转换为png图片
    :param filename: 图片文件名
    :return:
    """
    img = Image.open(filename)
    rp = ReParser()
    c_filename = rp.replace(r'\..*$', format, filename)
    img.save(c_filename)