Image export for steps 13-15 is broken

[Netherquark]

Might be relevant to YUV domain. Not sure.

[Netherquark]

switched to TIFF from PNG in a4a6f00

TIFF 6.0, Part 2: TIFF Extensions supports YCbCr representations, but its being encoded into a super tall weird gray image according to Shotwell. Need to mess with the saving commands a bit.