Via Say Uncle I found Foxit, which is a pdf reader.  I have always disliked how Adobe Reader bogged down my machine (Uncle called it "bloatware").  So now I have been able to get rid of that beached whale of a program and use Foxit.  It's way faster, and way smaller.  Unfortunately, it doesn't look like there's a Firefox plug-in for it yet, so as far as I can tell it can't be used to display a pdf within the browser.  I never do this anyway, because it always bogged down Firefox for so long that I've always just downloaded the pdf and then displayed it outside of Firefox.

The other one I recently found is called MWSnap.  This one is for taking screen captures, and can save in a variety of formats including bmp and png.  Much better than the old one I was using that saved only in an extremely lossy jpg.

Both are freeware.