Toggle images bookmarklet

(function() {
  var CLASS = 'hide-images';
  var STYLE = 'html body,html body *,html body *::before,html body *::after { background-image: none !important; }  html body img, html body svg, html body video, html body iframe { opacity: 0.02 !important; }';
  var block = document.querySelector('.' + CLASS);

  // add/remove style block to override images
  if (block) block.remove();
  else {
    block = document.createElement('style');
    block.className = CLASS;
    block.innerHTML = STYLE;
    document.head.appendChild(block);
  }  
})();


/////////////////////////

// Unfortunately you have to let these load before it will hide them
javascript:(function(){var a="hide-images",b="html body,html body *,html body *::before,html body *::after { background-image: none !important; }  html body img, html body video, html body svg, html body iframe { opacity: 0.02 !important; }",c=document.querySelector("."+a);c?c.remove():(c=document.createElement("style"),c.className=a,c.innerHTML=b,document.head.appendChild(c))})()

This might be an approach to remove iframes/images
http://dyn-web.com/tutorials/iframes/hidden/

And another approach: (mess with opacity, won't save laptop battery though.)
https://medium.com/@zachcaceres/dont-use-display-none-to-hide-iframes-in-safari-b51715eb22c4

https://blog.logrocket.com/the-ultimate-guide-to-iframes/

// This would remove all img elements (could do same with iframes, maybe do something similar with adding hidden to the element)
https://codepen.io/anthonyLukes/pen/DaGtF