It was the golden era of "multi-image"-- multiple slide projectors that were programmed to fade on and off or into each other to replicate the feeling of film. All of this movement was "programed" to the pre-recorded soundtrack and the end result was often mistaken for a "movie". But it was cheaper than the movie, and the crisp look of slides could be dramatic on a 40 foot screen.
To prove our capabilities, we did what I recommend to all starting producers-- we created a demo show-- called the "2 minute show", since new member of the Sales and Marketing Executives (SME) were allowed to spout off about themselves for two minutes.
We let the pictures do the talking. 9 projectors, one screen / image.