jquery change picture source

$("#my_image").attr("src","second.jpg");//change image src with jquery
$("#myImageID").attr("src","images/my_other_image.png");

//change image src plain javascript
document.getElementById('myImageID').src="images/my_other_image.png";
$("#my_image").attr("src","second.jpg");// https://codepen.io/kman/pen/dXjpoX
// Stockphotos JS

$(document).ready(function(){
  var flag = 0;  
  $("button#changeSize").click(function(){
    if(flag == 0) {
      $("#dummyimage").attr("src","http://dummyimage.com/350x155/");
      flag = 1;
    }
    else if(flag == 1) {
      $("#dummyimage").attr("src","http://dummyimage.com/450x255/");
      flag = 0;
    }
  });
});$(document).ready(function () {
    $('img').click(function(){
        $(this).attr('src','images/download.jpeg')
      })
})