It might be that the software you’re using for your blog is degrading quality to save bandwidth. It might also be that you’re using colour profiles or something that your browser cannot display the way you’re used to – test this by viewing the image in your browser (e.g. in most browsers, you’d select File->Open File… or something like that).

So I checked it in the browser they look good. I think it’s blogger. And flickr now looks better too.