Here is the HTML just before $dompdf->render() and $dompdf->output() are called:
<img src="http://www.example.com/images/Logo.png" />
All other invoices display the image fine when viewing in the browser, or printing it, or emailing it as HTML. When I click 'Generate PDF' inside of our application, it renders the invoice in PDF, except the logo is missing. I have put a debugging line in to email me the raw HTML it sends to the render(), and it looks fine to me.
Does anyone have any idea why dompdf won't display this image?
An idea: if you are providing full URI to the image it is treated as external, so defined costant DOMPDF_ENABLE_REMOTE must be set to true.