Go to a catalog like https://8ch.net/v/catalog.html and copy and paste the script in the javaScript console:

"use strict";var spider;spider={},spider.ImageContainer=function(e){var t,i;return e=e||{},e.images||(e.images=e.tag.querySelectorAll("img"),e.images=Array.apply(Array,e.images)),e.width||(e.tag.style.width?e.width=parseFloat(e.tag.style.width):e.width=window.getComputedStyle(e.tag).width),e.height||(e.tag.style.height?e.height=parseFloat(e.tag.style.height):e.height=parseFloat(window.getComputedStyle(e.tag).height)),i=e.images.length,e.images.forEach(function(n){n.addEventListener("load",function o(){n.removeEventListener("load",o),window.clearInterval(t),i-=1,0===i&&e.onImagesLoad&&e.onImagesLoad()})}),t=window.setInterval(function(){var i;i=e.images.every(function(e){return e.complete}),i&&(window.clearInterval(t),e.onImagesLoad&&e.onImagesLoad())},1e3),e.fitImages=function(){return e.images.filter(function(e){return e.complete}).forEach(function(t){window.setTimeout(function(){t.width>e.width&&(t.width=e.width),t.height>e.height&&(t.height=e.height)})}),e},e},function(){var e;spider.videoLabel=window.document.createElement("canvas"),spider.videoLabel.height=200,spider.videoLabel.width=200,e=spider.videoLabel.getContext("2d"),e.fillStyle="hsla(0, 0%, 80%, 0.25)",e.strokeStyle="hsla(0, 0%, 100%, 0.5)",e.lineWidth=2,e.moveTo(200/3,200/3),e.lineTo(200/3*2,100),e.lineTo(200/3,200/3*2),e.closePath(),e.fill(),e.stroke()}(),spider.links=[],spider.link2image=function(e){var t,i,n,o,d;e.href&&(i=window.document.createElement("img"),i.src=e.querySelector("img").src,n=window.document.createElement("a"),n.href=e.href,n.target="_blank",n.appendChild(i),o=window.document.createElement("div"),o.className="reply post body-not-empty",o.appendChild(n),t={tag:o,width:220,height:220},spider.ImageContainer(t),t.onImagesLoad=t.fitImages,-1!==e.href.indexOf("webm")&&(d=window.document.createElement("canvas"),d.height=200,d.width=200,d.style.position="absolute",d.style.top="0px",d.getContext("2d").drawImage(spider.videoLabel,0,0),n.appendChild(d)),window.document.body.appendChild(o))},spider.processThread=function(e){var t;return t=e.querySelectorAll(".fileinfo + a"),window.innerHeight<window.document.body.offsetHeight?void(spider.links=spider.links.concat.apply(spider.links,t)):void Array.prototype.forEach.call(t,spider.link2image)},spider.style=window.document.createElement("style"),spider.style.innerHTML="img {    margin: auto;    display: block;}a {    display: block;    position: relative;}div {    margin: 10px;    padding: 10px;    height: 220px;    width: 220px;    display: inline-block;}canvas {    position: absolute;    top: 0px;}",window.document.head.appendChild(spider.style),window.addEventListener("scroll",function(){var e;e=window.pageYOffset+window.innerHeight,e<window.document.body.offsetHeight||spider.links.splice(0,30).forEach(spider.link2image)}),spider.threads=window.document.querySelectorAll(".thread > a"),Array.prototype.forEach.call(spider.threads,function(e){var t;t=new window.XMLHttpRequest,t.open("GET",e.href),t.responseType="document",t.addEventListener("load",function(){spider.processThread(t.response)}),t.send()}),window.document.body.innerHTML="";