Image from sendFile() display in mpdf

I has some image file located outside web accessible folder.
I use this code in controller to get the image file and display it in a page.

return Yii::$app->response->sendFile($filePath);

It work.
My problem is when i use the same page as content for kartik mpdf extension to generate pdf, the page is displayed as a generated pdf, but without the image.
How to display the image in the generated pdf?
I already test display image located inside web accessible folder using Html::img() method, it work just fine. So problem is only with image from Yii::$app->response->sendFile($filePath).

show your relevant code no just that one liner!

For pdf you will have to embed the image into the pdf, or alternatively instead of sending the file, render an html view that contains the image and print that page to pdf.