Please note this is an old forum thread. Information in this post may be out-to-date and/or erroneous.
Every phpdocx version includes new features and improvements. Previously unsupported features may have been added to newer releases, or past issues may have been corrected.
You just need to add a placeholder in the document, like $IMAGE$. And then use replaceTemplateVariableByHTML replacing $IMAGE$ with an image tag like <img src=""/>
You can check easy/ReplaceTemplateVariableByHTML.php example.