var canvas;

        function setup() {
          // put drawing code here
          canvas = createCanvas(windowWidth, windowHeight);
          background(random(255), random(255), random(255), 50);

          button = createButton("Image Speichern");
          button.mousePressed(saveImage)
          button.position(windowWidth - 180, windowHeight - 50)
        }

        function draw() {
          // put drawing code here
          frameRate(2)
          noStroke();
          fill(random(255), random(255), random(255), 70);
          ellipse(random(windowWidth), random(windowHeight), random(10, 300), random(10, 300));
        }

        function saveImage() {
         saveCanvas('RandomKreis', 'jpg');
        }