Got Acrobat or Pitstop?

PrintDriver is a grande format digital print dude. His advice/opinions may not apply to the 4color/offset/web world of printing

Or... if you have Acrobat setup properly, and it's a fairly 'normal' PDF, you can try the Cmnd (or Cntrl) click on the image with the objet touchup tool (or right mouse button menu) which will enable the 'Edit Image' function that boots the image into Photoshop for editing where you can check their colour, rez, etc.

Another option is to try opening the PDF in AI or CorelDraw for info.

One more-- go to www.quite.com and download the trial version of Quite-A-Box-of-Tricks. Even if you don't buy the full version, you can keep this Acrobat plugin installed and use it's very handy Info palette tool which gives you rez and colour depth info just by clicking on an image.

Of course, sometimes people just want to know if the PDF they've just made hasn't somehow got low-rez screen shots inserted by mistake. And just a simple zoom in on the image does this, once you get the hang of 'reading' pixel rez by eye.