I had problems with Pages 2 a few times with particular images (scanned photos imported after editing with GIMP, I think) not showing up correctly in Adobe Reader (Preview was fine) – but only when the PDF had been exported from Pages using one of the many settings available for PDF making. On another export setting the same image would show up OK.
It wasn't consistent: other images prepared the same way as the problem image were fine, and the export settings (Better in the first case, Best in the second) where problems occurred were different.
My guess had been that certain photos were compressed by Pages/OSX in a way that was problematic for Adobe, but the instance where the Best setting was used seemed to bely that, since presumably under Best the images are not modified.
In each case I was able to export the PDF a different way - using the ColorSync filters - getting pretty much the same compressed size but with no problems with the images.
So, I always make sure I test my PDFs on different computers with versions of Adobe Reader before sending them out, either to a printer or for posting on a website. But that's only happened to me twice: usually there's no problem.
The other thing that has caused a problem with the printer (opening my PDF in InDesign) was a photo upon which I had multiple transparent layers of overlapping text. It was easily sorted by using a single layer. But others have had problems with layers/transparencies rendered in PDFs in Pages in the past.
There are many ways to export as a PDF or another image format, though. Open Applications/Utilities/ColorSync and look in the Help menu. Also in Preview, if you have Leopard. The Save As... menu in Preview 4.0 gives the following options, as well as containing all the ColorSync filters if you choose Format: PDF -
Format: GIF, JPEG, JPEG-2000, Microsoft BMP, OpenEXR, PDF, Photoshop, PICT, PNG, SGI, TGA, TIFF
So yes, there is a way to send the PDF as a TIFF if you really want to.
Rhys