// image variable
PImage david;

int y = 0;
int direction = 1;

// run once and only once
void setup() {
 size(300,300); 
// background(255);
// load the image
david = loadImage("bowie.jpg");

// tinting is NOT optional
// tint(gray, alpha) or tint(val1,val2,val3,alpha)l
tint(245,124,219);
}
void draw() {
 frameRate(60);
 background(255);
// display image (name, x, y, width, height) (in pixels)
image(david,20,30+y,50+y,100);
 y+=direction; 
 
// yo line, when your y value is the height of the box turn around
  if (y > height) {
   //line (0,50,100,100); 
   direction = -1;
  }
  
// yo line, when your y value is less than zero, turn around
  if (y < 0) {
   //line (0,50,100,100); 
   direction = 1;
  }

}