Deep image compositing is a way of putting together different pictures to make one big picture that looks like it was all one picture from the start. Imagine you have a big sheet of paper and some pictures on smaller pieces of paper. You want to make one big picture from all the smaller pictures.
With deep image compositing, you can take each smaller picture and make it like a cake with lots of different layers. Each layer is something different in the picture, like the colors or the shadows. Then you can take each little cake layer and put it together with the other cake layers to make one big, delicious cake of a picture.
The cool thing about deep image compositing is that it allows each layer in the cake to move independently. This means if one part of the picture needs to change, like if someone moves or if the lighting changes, you can just change the one layer without having to redo the whole picture.
It's like building with Legos! You can build a big castle by putting together lots of little Lego pieces. Each piece can be one color or one shape, and you can build it up as high as you want. Then, if you want to change something, you can just take one piece off and put a different piece in its place.
So, deep image compositing is like building with cake layers or Legos to make one big picture that you can change parts of without having to redo the whole thing. Yum!