Try clapping your hands and see what happens to value on the Processing side; I’m guessing that it will increase. When you know how high it goes then write code something like this:
if (value > someNumber){
image(myImage, x, y);
}
i.e., if number is above a certain value, display my image.
You can read how to load and display an image here: https://processing.org/reference/image_.html