Default theme jumps to the right when adding a big image to a post

hey everyone,
im new to this so im using the default theme but playing around with it. after a while i realized that when i went from the actual blog to the “about” page or whatever the whole page would jump to the right, about 5-10 px or something. took me two hours to figure out it was because of an image i inserted into a post. i used a smaller image and everything was fine, used a bigger one again and same problem. thats the blog: chrisbmurray.com/blog i installed a fresh default theme and it still had the problem so im sure its not from my tweaking around with it..thanks for the help