Normally we will use align="absmiddle" to make an image align in the middle between a HTML element/object, e.g:
< input name="text1" type="text" maxlength="17">< src="button_ok.gif'" alt="OK" style="margin-bottom:1px;" align="absmiddle">
or
<img src="images/icon_diamond.gif" alt="" align="absbottom">
You will get error when you try to validate your page with W3C Markup Validator (http://validator.w3.org/check).
How to solve?
Use this:
<img src="images/icon_diamond.gif" alt="" style="vertical-align:bottom">
Same to:
<img src="images/icon_diamond.gif" alt="" style="vertical-align:middle">