​

function setup() {

    var uploadBtn = createFileInput(imageUpload);

    canvas = createCanvas(500,400);

}

​

function imageUpload(file) {

    img = loadImage(file.data,function(){

    // img.filter(GRAY,0.5);

    image(img, 0, 0, width, height);            

    })        

}

​

function mouseDragged() {

  noStroke()

  fill(0)

  ellipse(pmouseX, pmouseY, 10, 10)

}