Let's say you have the following code:
<a href="#"><img src="path/to/image.ext" alt=""/></a>
In certain cases, like when the image is part of the template and has to be touching the rest of the template, such an instance can break your design. Many immediately think it is either the padding or margin of the anchor element, but soon later realize reducing them to zero was in vain. There are a few ways to fix this, depending on the browser. However, the absolute way to fix this is using line-height:
line-height: 0;
The problem was the that the browser was rendering properties for fonts, though there was no text within the anchor element.
