I have been wrestling with the way that WLW treats images in a post.
It appears that the theme I am using has styles that over ride what WLW does. There are classes set in the CSS for image alignment.
If I tell WLW to align an image right is sets the attribute, but this is reset by the CSS. So even though it should be on the right the image is on the left. If I go into the wordpress editor and set the alignment is uses the proper CSS from the stylesheet.
I have looked at other Word Press themes and this CSS seems to be pretty common. In order for this to be a truly useful tool I think WLW needs a way to work with this.