[css] 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;"/>

For a bootstrap button:

display: table; 
margin: 0 auto;

I remember someday that I spent a lot of time trying to center a div, using margin: 0 auto.

I had display: inline-block on it, when I removed it, the div centered correctly.

As Ross pointed out, it doesn't work on inline elements.

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.

put this in the body's css: background:#3D668F; then add: display: block; margin: auto; to the img's css.

there is a alternative to margin-left:auto; margin-right: auto; or margin:0 auto; for the ones that use position:absolute; this is how:
you set the left position of the element to 50% (left:50%;) but that will not center it correctly in order for the element to be centered correctly you need to give it a margin of minus half of it`s width, that will center your element perfectly

here is an example: http://jsfiddle.net/35ERq/3/

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.

You can center auto width div using display:table;

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

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

img{display: flex; max-width: 80%; margin: auto;}

This is working for me. You can also use display: table in this case. Moreover, if you don't want to stick to this approach you can use the following:

img{position: relative; left: 50%;}