Auto margins don't center image in page

In this example the image is not centered. Why? My browser is Google Chrome v10 on windows 7, not IE.

<img src="/img/logo.png" style="margin:0px auto;"/>

add display:block; and it'll work. Images are inline by default

To clarify, the default width for a block element is auto, which of course fills the entire available width of the containing element.

By setting the margin to auto, the browser assigns half the remaining space to margin-left and the other half to margin-right.

You can center auto width div using display:table;

div{
margin: 0px auto;
float: none;
display: table;
}

Under some circumstances (such as earlier versions of IE, Gecko, Webkit) and inheritance, elements with position:relative; will prevent margin:0 auto; from working, even if top, right, bottom, and left aren't set.

Setting the element to position:static; (the default) may fix it under these circumstances. Generally, block level elements with a specified width will respect margin:0 auto; using either relative or static positioning.

In my case the problem was that I had set min and max width without width itself.

Whenever we don't add width and add margin:auto, I guess it will not work. It's from my experience. Width gives the idea where exactly it needs to provide equal margins.