title: Does mosquitto_pub convert a binary file to ASCII?
body: <p>I am quite new to MQTT protocol and I am sorry if my question sounds stupid. I am publishing an image from a device and when I subscribe to it on CLI I can see some characters which are not in the binary format. So my question is when the image is published does it by default get converted to ASCII format and then sent or is it received in the ASCII format or some other format?</p>
  
  <p>The publish command I am giving is: </p>
  
  <p>mosquitto_pub --cafile /home/pi/nirupama/rootCA.pem --cert /home/pi/nirupama/certificate.pem --key /home/pi/nirupama/private.pem -h xxxxxxxxxxxxxx.iot.us-west-2.amazonaws.com -p 8883 -q 1 -d -t $aws/things/raspberry-pi/shadow/update -i mqtt_test -f /media/webcam/picture.jpg</p>
  
  <p>The subscribe command is:</p>
  
  <p>mosquitto_sub --cafile /home/pi/nirupama/rootCA.pem --cert /home/pi/nirupama/certificate.pem --key /home/pi/nirupama/private.pem -h xxxxxxxxxxxxxx.iot.us-west-2.amazonaws.com -p 8883 -q 1 -d -t $aws/things/raspberry-pi/shadow/update -i mqtt_test1</p>