You create a cms static block (cms/block) and dynamise it with widget, here an example:
<div class="confirmation"> <img src="{{skin url='images/image-order.jpg'}}" alt="" /> </div>
You then render this block :
echo Mage::getModel('cms/block') ->setStoreId(Mage::app()->getStore()->getId()) ->load(self::confirmationCmsBlockName)->render();
But the widget {{skin url=’images/image-order.jpg’}} is not executed and is display as {{skin url=’images/image-order.jpg’}}.
To execute the widget, you need to render as HTML a block and not a model
echo Mage::app()->getLayout()->createBlock('cms/block')->setBlockId(self::confirmationCmsBlockName)->toHtml();