I had a several page scanned document stored in PDF format that I needed to convert to PNG so I could upload it to a PayPal account to resolve a limited access problem. I found several solutions for Linux that produced inadequate image files. When I switched to my Mac OS X laptop, I opened the PDF in Preview. I selected “Save As…” from the File menu, selected “PNG” from the drop down menu and set the resolution to 300 pixels per inch. I hit the Save button, and the newly created PNG opened up. The quality was adequate, and the problem was solved.