I recently enjoyed this 2010 article on using OS X PDF services to send websites and docs to iBooks (Mac OS X Hints). All Mac geeks should give it a read, and the excellent comments as well.
Reading the hint made me take another look at the options on the handy PDF menu found at the bottom left of every print dialog. The list includes Save PDF to iPhoto, which is a bit odd since iPhoto won't import PDFs. (I have a memory that it once did, but Google disagrees). If you drop a PDF into iPhoto, you get a not supported dialog.
So I gave it a try. The results are interesting - iPhoto gets a JPEG for every page of the PDF. It's even documented ..
... This feature uses an Automator workflow to create a PDF printout, and then convert that PDF to a JPEG. The JPEG is then sent to iPhoto. This workflow is installed by Mac OS X and is stored in /Library/PDF Services/...
It's an obscure but handy feature. Alas, Automator never lived up to its 10.4 promises, it's languished ever since, despite the best efforts of Nyhthawk Production's curious site ... Mac OS X Automation (curious because it's not an Apple site, but Automator links to it).