You think that center means center. You think that if you click the center icon, you're done. I don't know why this isn't true but it's not true for me.
Here's my suspicion of the morning and if someone knows better, please let us know.
In Expression Web, it's not considering the center of the page.
It's thinking of the image as text. Because the image stands alone like the beginning of a paragraph, Ex Web is applying an indent.
Here's the code for the images from the document. I've put the code in red so you can discern it from the other stuff but blogger thinks I'm trying to write code so I had to turn it into an image. Sheesh!
Since it's not text, the program shouldn't be indenting it. But when I converted the document in Word to html, that's what you get.
What I did was leave the Design mode and go into Code and delete that line in red when it referred to an image.
Then I went back to Design. Centered and reCentered.
That solved the problem of images not being centered. I think it also explains why other things aren't truly centered as well but I'm not going back and reformatting everything already published. Sorry. Still it's nothing anyone has complained about. YET.