If the URL ends in .pdf, it is a page stored in portable document format. If you have installed Adobe Reader, it will be displayed in Safari as if it were another web page - using an Adobe Reader resource - by default.
You can rotate this image - after saving it locally as a pdf by pressing the floppy disk icon on the left end of the menu area of the page - in either Adobe Reader or Apple's Preview application.
You can rotate this image - after saving it locally as a pdf by pressing the floppy disk icon on the left end of the menu area of the page - in either Adobe Reader or Apple's Preview application.