obamaImage = None
beachImage = None

def setup():
    global backImage
    size(500,500)
    backImage = loadImage("beach.jpg")
    image(backImage,0 ,0 ,500 ,500)
    loadPixels()
    pixelsBack = pixels[0:]

    global frontImage
    size (500,500)
    frontImage = loadImage("obama.jpg")
    image(frontImage,0,0,500,500)
    loadPixels()
    pixelsFront = pixels[0:]

    for x in range(0, width):
        for y in range(0, height):
            i = x + width*y
            if (green(pixelsFront[i]) >= 150 and red(pixelsFront[i]) <= 80 and blue(pixelsFront[i]) <= 80) or \ #this is one case where there is high green and high red and blue
               (green(pixelsFront[i]) >= 100 and red(pixelsFront[i]) <= 20 and blue(pixelsFront[i]) <= 20) : #this is another case where there is lower green, but also low red and low blue
                    pixels[i] = pixelsBack[i] #mods the current selected pixels from pixelsFront when conditions are met, to be from pixelsBack

    updatePixels()