Check whether an image is loaded with JavaScript

// inline js
   <img src="https://secure.gravatar.com/avatar?d=wavatar" onload="javascript: alert('success')" onerror="javascript: alert('failure')" />
    
    
// external js

  <img src="https://secure.gravatar.com/avatar?d=wavatar"/>

  window.addEventListener("load", event => {
      var image = document.querySelector('img');
      var isLoaded = image.complete && image.naturalHeight !== 0;
      alert(isLoaded);
  });
    
    
    
courtesy  - https://www.techiedelight.com/check-whether-image-is-loaded-with-javascript/#:~:text=To%20determine%20whether%20an%20image,the%20image%20failed%20to%20load.