PImage[] images;
PImage maskImg; 
int current = 0;

void setup(){

  size(720,480);
  framerate(5);
  background(0);
  images = new PImage [5];
  for (int i=0; i<images.length; i++) {
    images[i] = loadImage ("file"+i+".jpg");
 maskImg = loadImage("file20.tga"); 
   }
}

void draw (){
  tint(255,150);
  image (images[current],0,0); 
  current = (current+1)% images.length;
  image(maskImg, 0, 0);
}