Images are stored in PImage variables. There are two main commands for using PImages: loadImage(), which loads an image file; and image, which draws it. Processing treats bitmaps just like any other drawing command; so, for instance, you would layer images by just putting one image() command first and another image() command after it.
image (img,x,y,width,height)img: a PImage variable
x,y: location to draw the image at.
width,height: how big to make the image. You can set these independently to scale, stretch, squash the image.
This example loads two images, one for a background, and one that follows the mouse.
PImage water;
PImage moth;
void setup()
{
water=loadImage("water.jpg");
moth=loadImage("moth.png");
size(600,400);
}
void draw()
{
float x;
float y;
background(0);
image(water,0,0,600,400);
x=mouseX;
y=mouseY;
image(moth,x,y,50,80);
}