Print to PDF creates a small file

When I print-to-PDF in Photoshop, a PSD file that is 1088px wide, will create a PDF file that is only 261 px wide.

I do understand that there are different ways to create the PDF - but I am curious why this method creates such a smaller size. Why is not a pixel per pixel duplicate? I've checked settings, and perhaps I'm missing something.

Thank you...