This simple library turns raster images into TSPL files for sending to a TSPL printer, like the inexpensive Polono PL60.
The PL60 does not ship with a arm64 or armhf linux driver, meaning it cannot run on a low cost Raspberry Pi. This bypasses that by reading any image format, resizing it to 4x6 and converting it, then sending the raw data directly to the printer.