These are adjustments that don’t change the underlying photo, just its appearance. The advantage is you can go back later to change or remove adjustments. The downside is there’s no support for layers or more complex effects.
Pixel-ba sed editing
This is the traditional way of editing digital images, by making permanent changes to the image pixels. It’s harder to roll back the process, but it enables much more complex manipulations, layered montages and composites.