Why is Flickr Posterizing my images?

I just got done uploading an image and was disappointed to see yet again that flickr is posterizing my data. Why does this happen? Is there a way to avoid this ? Is see it mostly in the shadows to the right of the center down in the mountain area.

IMAGE LINK: https://flic.kr/p/VdHP​uX

calypsob wrote in post #18364363
I just got done uploading an image and was disappointed to see yet again that flickr is posterizing my data. Why does this happen? Is there a way to avoid this ? Is see it mostly in the shadows to the right of the center down in the mountain area.

IMAGE LINK: https://flic.kr/p/VdHP​uX Killer Sunset from the Blue Ridge Parkway by Wes Schwarz, on Flickr

Can you show us the image before you uploaded it to Flickr so that we have something to compare it to.

https://drive.google.c​om …h479N_kZr6dTkzZ​lhwdUJwLTg here is a psd

I think John wanted the actual file you uploaded to Flickr.

(You didn't upload that massive PSD, did you?? That might explain a great deal, if you did.)

I downloaded your linked image and opened it in Photoshop so I could zoom in, and I really am not seeing any posterization. Your image is a bit out of focus, but I don't see any stepwise gradients like this. [EDIT: Also downloaded your PSD file and compared it with the Flickr image; the only difference I see is that the Flickr image isn't quite as sharp -- and it's downsized, of course. As a side note, it might be a good idea to use sRGB instead of Adobe RGB when uploading for web viewing.]

It could be that you're seeing differences in color between the web and Photoshop. The short answer is to convert and preview your image in sRGB colorspace while in Photoshop. The long answer is that web browsers are starting to accept ICC color profiles, and are starting to accept other colorspaces. Flickr may only accept sRGB still.

web browser color management guide

no I uploaded a jpeg, I dont think flickr would produce and image with a psd

I see some large chunky things going on in the shadows mid center to the mountains. Maybe it is simply a jpeg artifact.

I always save jpeg to srgb.

calypsob wrote in post #18365329
no I uploaded a jpeg

Ok, great! Then may we see that?

calypsob wrote in post #18365331
I always save jpeg to srgb.

Are you sure you proof in sRGB?

calypsob wrote in post #18365330
I see some large chunky things going on in the shadows mid center to the mountains. Maybe it is simply a jpeg artifact.

Yes, I think you're seeing jpeg artifacts (blocking) in the shadows. That's pretty common in shots like this. Here's a section zoomed at 1600 percent with contrast exaggerated to bring out the artifacts.