Hello,
We recommend you check the HTML Extended documentation (https://www.phpdocx.com/documentation/introduction/html-extended-to-word-PHP):
Options for each method are added with custom data attributes. You just need to write the option name after the prefix data-. E.g.: data-bold="true", data-type="start" o data-type="default".
You are not using the attributes correctly, you need to set custom data attributes: data-
In the Premium package (examples/Core/embedHTML/sample_6.php) you can find a sample that illustrates how to use phpdocx_image with a custom align:
<phpdocx_image data-src="../../img/image.png" data-imageAlign="center" data-scaling="50" />
Regards.