.jpg compression efficiency

[s2jrston]

Has anyone ever noticed that compositions with green subjects compress more efficiently than majority blue or red subjects? It seems that the file size of landscapes, with two thirds of the frame dominated with grass or trees, are smaller than say a shot of the ocean with an equal amount of blue water or majority blue sky. I've noticed this with a couple of my photos and today I noticed it with a close-up shot of a green dinosaur. Has anybody else noticed this phenomena or have an explanation?

 

[Robfasto]

I have noticed just the opposite. Photos with more green tend to be larger. Again it could have to do with how much they are compressed. I know using untouch images straight from the camera green pictures are almost always larger.

That is why pictures are always different sizes....

 

[s2jrston]

That makes sense. If green pictures are larger in their raw format then there is more repetitive data to compress. I know green light is the most abundant wave length in the visible light spectrum. The more of something then the more it can be compressed.