html - Image tag closing

Question

How to close image tag in HTML?

<img src="#"></img>

or

<img src="#" />

or

 <img src="#">

Answer 1

in xhtml:

<img src="#" alt="some explaining" />

the closing / is for backwards compatibility

in html5

<img src="#" alt="some explaining">

no need anymore to close the <img> tag, (the browser knows that it is self-closing)

more info here: http://www.w3.org/TR/html5/embedded-content-0.html#the-img-element (thanks to Chris)