Hello Jaime,
Thanks for working on this problem. I'm in favor of showing
how plots appear (hard to explain without a picture),
and I think all of the examples are good.
So for my part I'll say, go ahead.
It seems like a good idea to put the plots in one directory
and have all translations of the manual refer to that
(instead of maintaining multiple copies of the plots).
I'll take this opportunity to make a couple of cautionary
remarks, which, as usual, everyone is free to ignore.
The Maxima manual is large and getting larger all the time,
which is good, but I think there is some pressure to pick
and choose carefully. I'm usually against bitmap screenshots
(as much for their size as for the kind of stuff which is
typically shown) although sometimes there is no other way.
By the way there seems to be a minor typo --
"Veja mais exemplos na sec at m_cedillac?o plot_options."
under plot3d. Probably a misplaced @ or something.
All the best,
Robert Dodier