Photo Mosaic by Haligonian is an effect for After Effects and Premiere Pro that rebuilds every frame out of thousands of little photos. The result produces a visual texture, and close examination reveals that each image is in fact made up of many hundreds or thousands of smaller images.
Applied to footage, what was a single frame becomes a composite assembled from many smaller ones. A demo video is available, along with a tutorial from the developer for anyone getting started with the effect.
Photo Mosaic supports After Effects 2025, 2024 and 2023, and Premiere Pro 2025, 2024 and 2023. It was last updated on 20 October 2025, and it is listed as free here — check the developer's page for current licensing details.