Thanks for the replies. I tried changing the src to exclude the site URL like the above forum post suggested. Unfortunately, that did not work, but I did get the error to show up.
“mPDF error: IMAGE Error (https://ocalafarms.com/wp-content/uploads/2017/10/print-header.jpg): Error parsing image file – image type not recognised, and not supported by GD imagecreate”
Also, in my dk-pdf.index file, I have the image src = /wp-content/uploads/2017/10/print-header.jpg so I’m not sure why this error shows the full url. Any help would be greatly appreciated.