Images with lots of green in them have a larger file size?

[sltungle]

My dad mentioned something to me recently. He was saying that as he was going through pictures that he took on site for work (he's an engineer) he noticed something. Most of the images that had a lot of grass or leaves in them had a noticeably larger file size than those that didn't have a lot of green things in them and were simply of a building itself, or something like that.

We both chucked a few ideas out there, but neither of us actually know for sure what the reason is.

If there's a reason for it and it's not just some weird anomaly, then what is the reason for this?

[NorthernGate]

oh good job with your avatar you fucking space stealer mad face

[IhateValve]

Mythbusters

[Soviet Beef]

file format/dimensions of image

[Conro101]

^This

[Trooth]

Let's compare three jpegs. I'll assume that since you mentioned photos, we're dealing mostly with jpegs, but it's always possible that multiple file types were involved.
[img]http://img31.imageshack.us/img31/926/redn.jpg[/img]
[img]http://img31.imageshack.us/img31/2880/greenbe.jpg[/img]
[img]http://img686.imageshack.us/img686/8201/bluer.jpg[/img]

Looks like they're all 10.6 kb
You can save them yourself to check.

[sltungle]

[QUOTE=Soviet Beef;19271255]file format/dimensions of image[/QUOTE]

They'd all probably be the same dimension given that it's from the same camera (camera was a crappy 6 megapixel one), and the images were jpg.

[anklyne]

It's probably because there's lots of different shades of green when it comes to grass and other plants because of natural variation in leaf colouring and shadow. Having more shades/amount of colours in an image increases the file size.