I know I've solved this problem before, but I can't remember or find the solution, so here I am...
In Firefox 3.5 this code causes an undesirable blue border around the image. How do I get rid of this blue border?
<a style="text-decoration: none;" href="index.html">
<img src="http://www.google.com/logos/stpatricksday10-hp.gif" />
</a>
a img { border: none; }
Should do the trick (works in IE6).
Try setting image border to 0 px.
来源：https://stackoverflow.com/questions/2466590/how-to-get-rid-of-box-around-linked-image