Thanks Guitarfreak.
The big ol' original version showed me that it must have been very hot on this day. Because there's a lot of chromatic noise in it. Happens with my pictures too, the moment when the camera body gets warmer than 20 C.
I have made some pictures recently, on the very same day with the same cam to test it. Morning, Midday, Afternoon, Evening. Camera on a tripod, not moving. Same "Poster" on the wall. Difference was only the temperature.
And whenever the camera (due to the room temperature, i live in an appartment directly under the roof) got warmer... the color noise level raised kinda exponentially... (which is not a secret, hey, that is just dull physics on the sensor).