Update.-- After working with the NPS folks at Mt. Rainier NP and using the Apple discussion forums I found the answer to the problem is to use one of Apple's embedded application, Preview. Just open the PDF document in Preview and use the "Save As" tool to resave it as a PDF, preferably new if things go wrong but overwriting the original works if you can retrieve it or have a copy elsewhere. The Preview application assembles all the sliced images, maps and graphs into single files into the new PDF, which you can now import into your iPad. It will display properly with all the graphics
Original Post.--I've written that I purchased an iPad and then followed up with advisories from my learning curve. I was really interested in using the iPad for reading PDF's but Apple didn't put a PDF reader in the applications, only in the Safari browser. The one in Safari, like the browser itself, is a less than full feature reader. They relied on third party developers for PDF readers, and there are a lot, most of which aren't that good.
Anyway, I found three which are good, PDFMate, GoodReader and Stanza. Each have a different interface and features. The important difference I found testing some National Park Service and US Geological publications is the limit to the applications. Only GoodReader seems to have a very high (large) file limitations. I loaded a 300+ MByte file of one document. The other two tried and bailed on the document.
That's not the issue with this post as everyone will judge which PDF reader that works for them. My argument is that any PDF reader on the iPad can have problems with the images, maps and graphs in some reports. And after some testing I discovered part of the reason, or so I think. When I download the NP Carbon River ESA for Mt. Rainier NP, I found the report was fine but the vast majority of the images were blank.
And using the power of Acrobat Pro (meanng doing a lot of Adobe Acrobatics) I found the publications folks either composited the images from slices of the original image (8-10 slices) or combined separate images, both of which won't render on the iPad. I then tested it downloading some other reports, mostly older ones or other agencies and had no problems with the images, because they were single complete images.
My point? Well, the iPad has a way to go, and I understand there will be an upgrade in the operating system in November. Yippe, especially if it's as advertised to add multi-tasking. I would like to see a better Safari browser and PDF compatibility, but since Apple is suport e-Pub format (iBooks), I'm not holding my breath.
The key is getting publications other than popular books or magazines to produce ePub format at the time they produce the PDF or other electronic versions. This way people have choices of using a reader or iPad's free iBooks. And this has to be done from the original, which every word processor and publication application has the tool or plug-in. And yeah, again, I'm not holding my breath.
In the end, though, if you encounter problems with images, maps and graphs in a PDF, it's not you, but sadly there's not much you can do about it.