I would say those big squares are the textures of very high altitude clouds, like stratus or so. Maybe, when resizing, you damaged some information, like alpha channel for transparency, or something like that, leading to an incorrect display...
I get kinda the same thing in my "night" scenery. It's like a big purple band or 'rainbow' that stretches from one horizon to the other. I don't want to mess up anything else so I chalk it up to experience. Luckily the purple is a really dark color so I just take advantage of it as a tool in dead reckoning flight.
Keni
The only thing you never want to hear a Navy ordnanceman say.