How to show an image via shortcode

Question

This is basic function to create a shortcodes.

Put this code in your functions.php

function smile_shortcode() {
    $output = get_template_directory_uri() . '/images/smile.png'; // put your smile image here
    $_image="<img src="" . $output . '">';
    return $_image;
}
add_shortcode('smile','smile_shortcode');

Then go to your dashboard and post editor. Remember to put [smile] in your post.

More: http://codex.wordpress.org/Function_Reference/add_shortcode