Having tried to embed a couple of videos with the use of either
Insert>Object>Video or Insert>Movie and sound did not produce the expected
result. Thus, having removed the objects created I pasted a start image and set
an interection of running the video by a external player. As all was well I left
it as it was. To the point now.

After all the experimenting I ended up with a file weighing almost 150 mb. I
discovered that only because I wanted to send it somewhere. I though, maybe the
videos I linked have been stored in the file itself so I made a duplicate and
removed all the links. Well that did not work. However, having opened the file
with an archive manager the videos I tired to emebed appeared  to be saved in
the media folder.I thought " I'll remove them then." but it did not work as I
could not open the file after deziping removing and ziping and renaming it
again. In the end I just copied all of the prepared slides and changed the
interaction paths to the proper ones. And guess what - the presentation file
wheighed 5.5 mb. I do not know where this is a bug or just a feature request so
I'll write what I would expect : Either autmoatic media removal when it is not
being used in any of the slides or (which in my opinion is a better option) a
manual tool for removing those media files.

Mind you I tried using presentation minimizer but it did not help prevent movies
from saving in the file.