Python ZPL2 Library generates ZPL2 code which can be sent to Zebra or similar label printers. The library uses only millimeters as units and converts them internally according to printer settings.
l = Label(65,60)
height = 0
l.origin(0,0)
l.write_text("Problem?", char_height=10, char_width=8, line_width=60, justification='C')
l.endorigin()
height += 13
image_width = 55
l.origin((l.width-image_width)/2, height)
image_height = l.write_graphic(Image.open('trollface-large.png'), image_width)
l.endorigin()
l.origin(0, height+image_height)
l.write_text('Happy Troloween!', char_height=5, char_width=4, line_width=60,
justification='C')
l.endorigin()
print l.dumpZPL()
l.preview()This will display the following preview image, generated using the Labelary API: 
The generated ZPL2 code is:
^XA^FO0,0^A0N,120,96^FB720,1,0,C,0^FDProblem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appy Troloween!^FS^XZ
- PIL