- p = popen(["compare", '-metric', 'AE', '-fuzz', '5%', '-extract', '250x250', '/tmp/ref.png', image, '/tmp/delta.png'])
+ delta_image = demo.replace('/', '-') + '.diff.png'
+ p = popen(["compare", '-alpha', 'opaque', '-metric', 'AE', '-fuzz', '5%', ref_image, image, delta_image])