I'm having trouble when I place approx. 5 animated gifs, each about 40 seconds long (with other slides and transitions in between). I tried changing the length of time the slide with the gif in it would run for, but it does not seem to have an effect. I have added a delay after one of the animations run, but I don't see it happen in the preview.
Is there any tricks to working with many animated gifs?
Use small simple animated looping gifs with few colors and few frames like the animated gifs in the library.
A 2 second gif looping for 40 seconds would probably be better than a 40 second gif
If you are working with GIFs larger than about 300kb you might consider rethinking your strategy.
If you want to add 40 second gifs or video clips, you should probably use video editing software to add those things in post processing.