import PythonMagick

img = PythonMagick.Image('a.pdf')    # use your full path here
img.write('original.jpg')

imgLowRes = PythonMagick.Image(img)  # make a copy
imgLowRes.resize('220x')
imgLowRes.write('lowRes.jpg')

img.resize('48x')
img.write('thumb.jpg')