Why an img? A background image would make more sense.
But if it has to remain an image, I wonder if this has to do with
- the lack of a doctype
- browser default stylesheets adding padding and/or margin to the created-by-the-browser html and body tags (try setting both of these to 0 for both elements in your <style> tag)
- IE has some known issue with uneven pixel numbers, but I don't remember the details. If the image is even-numbered width, does the problem go away? I think it was called odd-numbered pixel shift.
Actually I'd do all three of these, unless again you can switch a foreground image to a CSS background image, which arguably makes way more sense since this looks presentational. Or does it open up at some point?