Don, from your description of "slides" it sounds very much like a Powerpoint presentation.

Having made several powerpoint presentations, rest assured there was allot of work your granddaughter and daughter spent on the P.P.S.  

I've got a degree in computers which involved knowing powerpoint inside and out, and it takes time.  From your description, they did a very good job putting the show together.

You're right the sentimental, "from the heart" gifts mean so much more than buying some doodad off a store shelf.

LOL.. I've got the knowledge/training/software to do P.P.S. just not the other part....