[html] Center image using text-align center?

Only if you need to support ancient versions of Internet Explorer.

The modern approach is to do margin: 0 auto in your CSS.

Example here: http://jsfiddle.net/bKRMY/

HTML:

<p>Hello the following image is centered</p>
<p class="pic"><img src="https://twimg0-a.akamaihd.net/profile_images/440228301/StackoverflowLogo_reasonably_small.png"/></p>
<p>Did it work?</p>

CSS:

p.pic {
    width: 48px;
    margin: 0 auto;
}

The only issue here is that the width of the paragraph must be the same as the width of the image. If you don't put a width on the paragraph, it will not work, because it will assume 100% and your image will be aligned left, unless of course you use text-align:center.

Try out the fiddle and experiment with it if you like.