IE8 Tab/Button Background 1px line

I have recently developed the above site, and as can be seem from the attached, I am getting a 1px line display glitch in IE8 for the background images of the primary menu buttons at the top of the page, as well as the 3 tabs buttons (View Videos & Photos, etc.) half-way down the page. This only happens at certain zoom levels.

With the 3 tabs, it seems as though in IE8, when at certain zoom levels, IE8 is repeating the top 1 pixel line of the backgound image at the bottom, even though I have just set the background-position to bottom.

If anyone can offer some advice on what is causing this issue, and how to fix, it would be much appreciated.



I have resolved this issue myself.

It looks like an IE8 bug to me, but as a workaround I just made the top 1px of the .png background images transparent, so when this bug occurs at certain zoom levels, it is invisible to the visitor.