title: postman - how to check picture size
body: <p>I am trying to write some tests in Postman (I am running the Postman Jetpacks packaged app, if it does matter) and I am facing some inconsistencies.</p>
  
  <p>The scope of my test is to verify the size (width and height) of a set of images against some predefined values.</p>
  
  <p>The scenario is like this: I make a call to a method that returns some urls, then I set the URLs as environment variables and then I verifying  the size of each picture. Below is the code I am using in Tests tab in Postman.</p>
  
  <pre><code>tests["Status code is 200"] = responseCode.code === 200;
  
  var data = JSON.parse(responseBody);
  
  //test that response contains the expected attributes
  tests["splash_image_url present"] = data.hasOwnProperty("splash_image_url");
  tests["home_image_url present"] = data.hasOwnProperty("home_image_url");
  tests["login_image_url present"] = data.hasOwnProperty("login_image_url");
  tests["register_image_url present"] = data.hasOwnProperty("register_image_url");
  tests["splash_logo_url present"] = data.hasOwnProperty("splash_logo_url");
  tests["bar_logo_url present"] = data.hasOwnProperty("bar_logo_url");
  
  //set each image URL as environment variable
  postman.setEnvironmentVariable("splash_image_url", data.splash_image_url);
  postman.setEnvironmentVariable("home_image_url", data.home_image_url);
  postman.setEnvironmentVariable("login_image_url", data.login_image_url);
  postman.setEnvironmentVariable("register_image_url", data.register_image_url);
  postman.setEnvironmentVariable("splash_logo_url", data.splash_logo_url);
  postman.setEnvironmentVariable("bar_logo_url", data.bar_logo_url);
  
  
  //extract images from each URL
  var splash_image_url = document.createElement("img");
  splash_image_url.src = environment.splash_image_url;
  var home_image_url = document.createElement("img");
  home_image_url.src = environment.home_image_url;
  var login_image_url = document.createElement("img");
  login_image_url.src = environment.login_image_url;
  var register_image_url = document.createElement("img");
  register_image_url.src = environment.register_image_url;
  var splash_logo_url = document.createElement("img");
  splash_logo_url.src = environment.splash_logo_url;
  var bar_logo_url = document.createElement("img");
  bar_logo_url.src = environment.bar_logo_url;
  
  //test the size for each picture 
  tests["splash_image_url width"] = splash_image_url.width === 640;
  tests["splash_image_url height"] = splash_image_url.height === 960;
  
  tests["home_image_url width"] = home_image_url.width === 640;
  tests["home_image_url height"] = home_image_url.height === 960;
  
  tests["login_image_url width"] = login_image_url.width === 640;
  tests["login_image_url height"] = login_image_url.height === 960;
  
  tests["register_image_url width"] = register_image_url.width === 640;
  tests["register_image_url height"] = register_image_url.height === 960;
  
  tests["splash_logo_url width"] = splash_logo_url.width === 310;
  tests["splash_logo_url height"] = splash_logo_url.height === 80;
  
  tests["bar_logo_url width"] = bar_logo_url.width === 155;
  tests["bar_logo_url height"] = bar_logo_url.height === 40;
  </code></pre>
  
  <p>The problem is that sometimes when running the request all or some of the picture size verification fail. If I continue to manually run the same request again and again it will eventually show all the tests passed. This inconsistency makes the test unreliable.</p>
  
  <p>I am missing something or doing something wrong? Is there a batter way to verify the picture size?</p>
  
  <p>Thanks</p>