Formatted code from analogpixel: http://www.analogpixel.org/blog/2011/09/13/msced-148-boxy-lady-take-2/#more-764

BoxyLady2.pde

// code taken from here: 
// http://www.analogpixel.org/blog/2011/09/13/msced-148-boxy-lady-take-2/#more-764
// and formatted for readability.
PImage pic1;
PGraphics pg;
boolean grow;
int box_size;

int MAXS = 40;
int MINS = 1;

void setup() 
{
    pic1 = loadImage("pic1.jpg");
    pg = createGraphics(pic1.width, pic1.height, JAVA2D);
    size(pic1.width, pic1.height);
    noStroke();
    grow = false;
    box_size = MAXS;
}

void draw()
{
    make(box_size);

    if (!grow)
    {
        box_size--;
        if (box_size < MINS) 
            grow = true;
    } 

    if (grow)
    { 
        box_size++; 
        if (MAXS < box_size) 
        {
            grow = false;
            exit();
        }
    }
}

void make(int i) 
{
    pic1.loadPixels();
    pg.beginDraw();
    pg.noStroke();

    for (int cc=0; cc < (width*height)/2; cc++) 
    {
        int x = int(random(0, width));

        int y = int(random(0, height));

        pg.fill(pic1.get(x, y));
        pg.rect(x, y, int(random(MINS, i)), int(random(MINS, i)));
    }

    pg.endDraw();

    image(pg, 0, 0);
    saveFrame("ani/image###.png");
}

void keyPressed() 
{
    if ( key == 's')
        saveFrame("images/image##.jpg");
}

Can easily make an animated gif from the results via ImageMagick on OSX:

convert -delay 2 -loop 0 *.png out.gif