Huh. That's bizarre. The post links to the JPEG directly for viewing and linking. Same JPEG so that ought to not happen.
Also your example doesn't look different to me, but I wear glasses. :D When I look at the link with an EXIF tool, I get the same info either way.
Try this: disable all of your plugins and switch to the Twenty Eleven theme. This is only temporary and you can re-enable the works in a minute afterwards. ;)
Clear your browser cache and visit
http://www.memoirmode.com/2012/07/16/whimsical-bohemian-style/
And make the same comparison.
I'm suggesting this because there are some javascript lazy loading going on so a plugin or the theme may be scaling or interfering with the image quality.