Premiere Pro: Possible to add several images on one video track?
If you want a hundred images at the same time, you need 100 layers. Often people will make a "pre-comp" which is a nested composition. You create a composition with only the images, then insert that composition into the main timeline. Any changes you make to the pre-comp will carry through even after you've laid it into your main video timeline. So your pre-comp will be the messy one, and your final comp will be nice and neat.