To resize an animation (+ position)
place animation ani, left, top, right, bottom
(or at least that's the command I remember, long time ago since I last used avi files)
And to wipe the animation from the screen, it's enough to use
cls.
So for example:
load animation "_.avi", 1
play animation 1
repeat : until animation playing(1) = 0
delete animation 1
cls
wait key
end
To freeze the game, and wait till the animation stopped (then wipe the screen).
It's the programmer's life:
Have a problem, solve the problem, and have a new problem to solve.