Rule34 Image Fit

Resize and center images on Rule34

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Rule34 Image Fit
// @namespace    potato_potato
// @description  Resize and center images on Rule34
// @author       potato_potato
// @version      0.1.0
// @grant        none
// @run-at       document-start
// @match        https://rule34.xxx/index.php?page=post&s=view&id=*
// @license      MIT
// ==/UserScript==

(() => {
    'use strict';
    function resize_image() {
        try {
            let image = document.getElementById("image");
            if (image != null) {
                image.style["object-fit"] = "contain"; // Protect aspect ratio
                image.style["max-height"] = "85vh"; // TODO: Investigate buggy behaviour when set higher than 85vh.
                image.style.width = "100%"; // Note that this doesn't clobber aspect ratio due to `object-fit: contain`.
            }
        } catch (e) {
            console.log('Error modifying image! Website structure change?');
            console.log(e);
        }
    }

    // We want to operate on the DOM after it is loaded, but BEFORE images are loaded and rendered, to
    // avoid the image rendering for a frame before suddenly being moved/resized.
    if (document.readyState == "complete" || document.readyState == "loaded" || document.readyState == "interactive")
        resize_image();
    else
        window.addEventListener('DOMContentLoaded', resize_image, false);
})();