Hello,
We recommend you to use a custom template with an image placeholder and a text placeholder surrounded by block placeholders, and then use the cloneBlock method (http://www.phpdocx.com/api-documentation/docx-path/clone-blocks-in-docx) to clone the block as many times as needed. This method is available since phpdocx 7 for Advanced and Premium licenses.
The options relativeFromHorizontal and relativeFromVertical available in the addImage method since phpdocx 7.5 can also help for that task.
But please note there's no a 'perfect' approach for that task, as a DOCX is not like a PDF that is 'painted' in fixed positions. It is more similar to HMTL, as it is painted 'dynamically'; so you should manage the contents of the blocks to avoid creating new extra pages. There's no way to know the content after a header.
Regards.