Yeah. I know what kind of transitions you mean ... Currently, my ideas of creating a game navigation system point to exactly what you have done ... with videos linking each image together.
I've done loads of tests, and one of them included this technique ... I only used photos taken with my digital camera inside my house, and discovered that the videos were just too long. They need to be very quick, since it may bore the player ...
A good example of this technique is used in REAH and SKIZM. Dragon Lore II used this technique as well ... Personally, I feel that it makes the game much more realistic and effective.
Fast and effective videos!
Goodluck with your endeavours!
Aaron Gwynaire
Sometimes does lead to darkness ...