How to show and hide PImages in an 'if' statement

Question

So I have waves appearing in sequence according to framerate and I want to show and hide them so that the images don't overlap. How would I implement a show boolean into my if statement? I appreciate the help alot

I'll paste the code below

class Waves {
  float x, y;

  Waves(float _x, float _y) {
    x = _x;
    y = _y;
  }

  void waveShow() {
    boolean show = true;
    //this is what I can't figure out
}

  void waveDisplay() {
    PImage[] waves = new PImage[3];
    waves[0] = loadImage("wave1.png");
    waves[1] = loadImage("wave2.png");
    waves[2] = loadImage("wave3.png");

    if (frameCount < 15) {
      image(waves[0], 0, 0);
    }
    else if (frameCount > 15 & frameCount < 30) {
      image(waves[1], 0, 0);
    }
    else if (frameCount > 30 & frameCount < 45) {
      image(waves[2], 0, 0);
    }
    else if (frameCount > 45) {
      background(scenes[stepperValue]);
      frameCount = 0;
    }
  }
}