Problem: You have an illustrated pdf that shows up fine on the mac but on the iPhone the illustrations are blank pages.
Solution: If you have a Mac computer, open this PDF file in Mac's standard Preview application, go to 'File' menu and select 'Save As' command. Then resave this file as a new PDF (make sure to change a file name, to preserve the original file unchanged). The new PDF file will be formatted in an iPhone-friendly way.