Web Design in a Nutshell, 3rd Edition

Borders

By default, when an image is linked, most browsers display a two-pixel-wide border around the image in the same color as the text links on the page (bright blue by default). In most cases, this blue border is visually unappealing, particularly around an image with transparent edges, but it is quite simple to turn it off using the border attribute.

The border attribute specifies the width of the border in number of pixels. Specifying a value of zero turns the borders off:

<a href="document.html"><img src="picture.gif"border="0" alt="" /></a>

Of course, if you are fond of the borders, you could just as easily make them really wide by setting a higher number value.

In the preferred CSS method, you set the border width for all the images in a document with one simple style rule using the border property:

img {border: 0;}

For more information on controlling the borders around images, see Chapter 19.