image quality problem

I can’t seem to figure out why in this post the images look pixelated and generally crappy:

http://blog.christaholka.com/2012/10/01/recent-work-duro-olowu/

when they are sized EXACTLY the same as the image in this post:

http://blog.christaholka.com/2012/10/01/recent-work-artist-goshka-macuga/

help please??!