[object-fit-cover-png-002c.html]
  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=856337
  fuzzy:
    if not webrender and (os == "android"): maxDifference=169;totalPixels=4054
    if not webrender and (os == "linux"): maxDifference=105;totalPixels=1782
    if not webrender and (os == "mac"): maxDifference=107;totalPixels=3428
    if not webrender and (os == "win"): maxDifference=105-107;totalPixels=1782-3502
