Impress Guide updates

I have started going through the Impress Guide chapters that Elliot has
been working on and replacing pictures with ones that were created for
the Getting Started with Impress chapter. These are only a subset of the
pix needed, but it might save others the trouble of redoing them.

While I'm at it, I'll do a few other things as I spot them. This may
include flagging changes that I know are needed but don't have time to
do on this pass.

--Jean

Excellent. Thanks for working on that Jean. I should be able to finish the
rebranding on the rest of them on my next pass.