Checking the "picture placeholders" option is one sure way to
make your pictures disappear, so don't do that.

A few things to try:
  1.  In Word, if you're working in Normal view, then switch to
Print Layout view (View | Print Layout), because objects that are
formatted as "float over text" (Word 97) or as something other
than "inline with text" (Word 2000, 2002, and 2003) are not
visible in Normal view.
  2.  In Word, click on Tools | Options | View tab | check the
"Drawings" box and uncheck the "Picture placeholders" box | Print
tab | check the "Drawing objects" box | OK.
  3.  If neither of the previous suggestions fixes the problem,
then try reducing the hardware acceleration setting in Start |
Control Panel | Display | Settings | Advanced | Troubleshooting.
 If this fixes the problem, then you might want to check the
website of the manufacturer of your video card/graphics adapter
to see if there is an updated driver available.