The Dymo LetraTag 200B is a Bluetooth label printer that comes with an iOS and Android app. The app only allows you to print text using a couple of installed fonts. This script implements the BLE protocol and allows you to print any image from your computer.
Use the MAC address printed on the back of the printer. Since the printer uses pixels that are twice as high as they are wide, the aspect ratio of the image is automatically adjusted.
python print.py --address aa:bb:cc:dd:ee:ff --image hello.png