<div class="col-md-4">text text text<span id="Implementation" class="green_text" onclick="myFunction()" >colored text </span> text text text text text text text text text text text</div>
<div id="contenu" class="col-md-3"></div>

<script>
function myFunction()
{
document.getElementById("contenu").innerHTML="<img class="image_contenu" src="http://path_to_image/ready_b.png" alt="ready_b" /><span class="title_function">texte texte</span><br class="clear">texte text text text text";
}
</script>

<script>
function myFunction()
{
document.getElementById("contenu").innerHTML="<div><img class="image_contenu" src="http://path_to_image/ready_b.png" alt="ready_b" /><span class="title_function">texte texte</span><br class="clear">texte text text text text</div>";
}
</script>