Image is not shown in PDF file using dompdf

use full directory path with .jpg image

It works for me.

 <img src="<?php echo $_SERVER["DOCUMENT_ROOT"].'/placeholder.jpg';?>"/>
 <img src="<?php echo $_SERVER["DOCUMENT_ROOT"].'\placeholder.jpg';?>"/>
 <img src="<?php echo $_SERVER["DOCUMENT_ROOT"].'./placeholder.jpg';?>"/>

Don't put full path of URL, just put foldername/filename.jpg

Example:

<img src="uploads/kuruvi.jpg">