Not generating failure images when width/height has different

[JeffreyKhangJiaFei]

Hi there,

Just to confirm, when I tried to change device list parameter and trigger flutter test, the test case will fail and not generating failure images, is this expected behaviour?

I double check the code in _goldens_io.dart , in line 203 to 211, it didn't include maskedDiff bytedata in the ComparisonResult.