import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc,properties):
    print("Connected with result code " + str(rc))
    client.subscribe("test/image")

def on_message(client, userdata, msg):
    with open("received_image.jpg", "wb") as image_file:
        image_file.write(msg.payload)
    print("Image received and saved")

client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, )
client.on_connect = on_connect
client.on_message = on_message

client.connect("121.40.129.71", 48835, 60)  # 连接到 MQTT 代理

client.loop_forever()