What happened to my photo? (background is pixelated?)

The contrast on a LCD monitor may change when looked from the side or top. That is why IPS panel are recommended for digital photography: they're much less prone to this. This "blurs" the possible explantions in your case. Is it posterization induced by a display artifact from looking from the side or is it posterization which is more readily visible when looking at the image with a different contrast ? The fact that is shows in the print would favor the first explanation.

The 1st step in your "detective" work should be to see if it's in the raw data to start with. The best tool is rawdigger .

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Thierry - posted as regular forum member