Processing Winnie

//PRE-SETUP//

//mic_minim//
import ddf.minim.*;
Minim minim;
AudioInput in;

float volumeIn; //Input value × 1000
float d; //diameter
float sa; //The difference between the input value × 1000 and the current diameter
float easing = 0.1; //The easing coefficient, large numerical value changes greatly
PImage head;
//array//
ArrayList p;
int move = 0;
float speed = 0.2;
float accel = 1.01;

//VOID SETUP//
void setup()
{

//mic_setup//
  size(1280, 800);
  minim = new Minim(this);
  in = minim.getLineIn(Minim.MONO, 512);
  fill(200,0,20,100);

  //img_setup1//
  PImage head;
  head = loadImage("doge.png");

//array_setup//
int x, y;
 color a;
  frameRate(60);
  background(0); // !!!! Do i have to state the backround here? !!!!

  //img_setup_for_array//
  image(head,width/2,height/2); // /!!!Do i have to state the position here? !!!!
  imageMode(CENTER);


 a=color(0);
  p = new ArrayList();
  for (x=0; x<width; x=x+1) {
    for (y=0; y<height; y=y+1) {
      if (get(x, y)!=a) {
        p.add(new pxl (x, y, random(-speed, speed), random(-speed, speed), get(x, y)));
      }
    }
  }
}

/// VOID_DRAW///

void draw() {

  //mic_draw//
   volumeIn = map(in.left.level(), 0, 0.5, 0, width*2); /// Convert input value to 0 to 500
  sa = volumeIn - d; //difference between the input value and the current diameter
  if(abs(sa) > 1) { //change the diameter only when the absolute value of the difference is greater than 1
    d = d + sa * easing; //0.1 min change in difference
  }
  image (head,width/2,height/2,d,d); // image size depends on the diameter

  int i;
  pxl a;
  background(0); // !!! Do i have to state the backround here again --not sure !!!
  for (i=0; i<p.size(); i=i+1) {
    a = (pxl) p.get(i);
    a.update(move);
  }
}

/// CLASS_PIXEL///
class pxl {
  float xspeed, yspeed;
  float x, y;
  color p;

  pxl (int a, int b, float c, float d, color e) {
    x = float(a);
    y = float(b);
    xspeed = c;
    yspeed = d;
    p = e;
  }

/// VOID_UPDATE///
  void update(int move) {   // how its exploded
    if (move==1) {
      xspeed=xspeed*accel;
      yspeed=yspeed*accel;
      x = x + xspeed;
      y = y + yspeed;
    }
    set(int(x), int(y), p);
  }
}

void explode() { // !!! I want to a statement that the picture should be exploded, if the picture radius/pixel   more than 500 x 500 px
  if (head = 500,500) {
    move = 1;
  }
}

void mousePressed() {
  redraw();
}

void stop() {
  in.close();
  minim.stop();
  super.stop();
}