I am not using Firebug for now.
The html code for the home page is :
<td align="right" width="100%" class="buttonheading">
<a rel="nofollow"
onclick="window.open(this.href,'win2','status=no,toolbar=no,scrollbars=yes,titlebar=no,menubar=no,resizable=yes,width=640,height=480,directories=no,location=no'); return false;" title="Imprimer" href="/cuisinesdebretagne/index.php?view=article&catid=78:chroniquedumois&id=3:vacancesenbleu&tmpl=component&print=1&layout=default&page="><img alt="Imprimer" src="/cuisinesdebretagne/templates/etoile/images/printButton.png"/></td>
<td align="right" width="100%" class="buttonheading">
<a onclick="window.open(this.href,'win2','width=400,height=350,menubar=yes,resizable=yes'); return false;" title="Envoyer" href="/cuisinesdebretagne/index.php?option=com_mailto&tmpl=component&link=929bd6bb427b289795f2a9d32fb95a52553db785"><img alt="Envoyer" src="/cuisinesdebretagne/templates/etoile/images/emailButton.png"/></td>
And for the page without the image :
<p class="buttons">
<a onclick="window.open(this.href,'win2','width=400,height=300,menubar=yes,resizable=yes'); return false;" class="editlinktip hasTip" href="/cuisinesdebretagne/index.php?option=com_mailto&tmpl=component&link=aHR0cDovL2xvY2FsaG9zdC9jdWlzaW5lc2RlYnJldGFnbmUvaW5kZXgucGhwP3ZpZXc9aXRlbXMmY2lkPSZpZD01JTNBbW91bGVzbWFyaW5pZXJlJm9wdGlvbj1jb21fZmxleGljb250ZW50Jkl0ZW1pZD0xMg=="> Recommander <a onclick="window.open(this.href,'win2','status=no,toolbar=no,scrollbars=yes,titlebar=no,menubar=no,resizable=yes,width=640,height=480,directories=no,location=no'); return false;" class="editlinktip hasTip" href="/cuisinesdebretagne/index.php?view=items&cid=2%3Arecettes&id=5%3Amoulesmariniere&pop=1&tmpl=component&print=1&option=com_flexicontent&Itemid=12"> Imprimer </p>
Joomla seems to know where to find images but not Flexicontent...