Imgur Proxy Auto-Loader

A robust userscript that unblocks Imgur images by pre-loading them through the DuckDuckGo image proxy and replacing the original links only after a successful load.

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您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Violentmonkey 暴力猴,才能安装此脚本。

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您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

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// ==UserScript==
// @name         Imgur Proxy Auto-Loader
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  A robust userscript that unblocks Imgur images by pre-loading them through the DuckDuckGo image proxy and replacing the original links only after a successful load.
// @author       Dormy
// @icon         https://i.ibb.co/4np6h8Sr/Gemini-Generated-Image-usz9ywusz9ywusz9.png
// @match        *://*/*
// @grant        none
// @license      MIT
// ==/UserScript==
 
(function() {
    'use strict';
 
    // =========================================================================
    // CONFIGURATION
    // Comma-separated list of web proxy prefixes. 
    // Currently set to only use DuckDuckGo as requested.
    // =========================================================================
    
    const PROXY_LIST_STRING = 'https://external-content.duckduckgo.com/iu/?u=';
    
    // Parse the string into a clean array
    const PROXIES = PROXY_LIST_STRING.split(',').map(p => p.trim()).filter(p => p.length > 0);
 
    if (PROXIES.length === 0) return; // Exit if no proxies are configured
 
    // Keep track of images currently being processed to avoid duplicate network requests
    const processing = new WeakSet();
    // Cache successful URLs so identical images on the page load instantly
    const successCache = new Map();
 
    // Core function: Test proxies recursively in the background
    function findWorkingProxy(originalUrl, proxyIndex, callback) {
        if (proxyIndex >= PROXIES.length) {
            console.error(`[Imgur Proxy] All proxies failed to load: ${originalUrl}`);
            return;
        }
 
        const proxyPrefix = PROXIES[proxyIndex];
        const testUrl = proxyPrefix + encodeURIComponent(originalUrl);
        
        // Create an off-screen image element to test the load
        const tempImg = new Image();
        
        tempImg.onload = function() {
            // SUCCESS! The image loaded. Pass the working URL back.
            callback(testUrl);
        };
        
        tempImg.onerror = function() {
            // FAILED! Log it and try the next proxy in the comma-separated list.
            console.warn(`[Imgur Proxy] Proxy failed (${proxyPrefix}). Trying next...`);
            findWorkingProxy(originalUrl, proxyIndex + 1, callback);
        };
 
        // Trigger the background network request
        tempImg.src = testUrl;
    }
 
    // Function to handle DOM elements
    function processImage(img) {
        let src = img.src || '';
        
        // Only target Imgur images that we haven't already started processing
        // Also ensure we aren't reprocessing an already proxied image
        if (!src.includes('imgur.com') || processing.has(img) || PROXIES.some(p => src.includes(p))) {
            return;
        }
 
        processing.add(img);
 
        // Strip responsive sizes so the browser doesn't override our proxied image
        if (img.hasAttribute('srcset')) img.removeAttribute('srcset');
        if (img.hasAttribute('sizes')) img.removeAttribute('sizes');
 
        // If we've already found a working proxy for this specific image, use it immediately
        if (successCache.has(src)) {
            img.src = successCache.get(src);
            return;
        }
 
        // Start the background testing process
        findWorkingProxy(src, 0, function(workingUrl) {
            successCache.set(src, workingUrl); // Save to cache
            
            // Only now, after the image has ACTUALLY loaded, do we replace it on the page
            img.src = workingUrl;       
        });
    }
 
    // Scan the page for images
    function scanDOM(root = document) {
        if (!root.querySelectorAll) return; // Ensure it's a valid DOM node
 
        // 1. Process standard images
        const images = root.querySelectorAll('img[src*="imgur.com"]');
        images.forEach(processImage);
 
        // 2. Handle <source> tags in <picture> elements
        const sources = root.querySelectorAll('source[srcset*="imgur.com"]');
        sources.forEach(source => {
            const parentPicture = source.closest('picture');
            if (parentPicture) {
                const img = parentPicture.querySelector('img');
                if (img) {
                    // Extract the base Imgur URL and let processImage handle it
                    let originalUrl = source.srcset.split(',')[0].trim().split(' ')[0];
                    if (originalUrl.includes('imgur.com')) {
                        img.src = originalUrl; 
                        processImage(img);
                    }
                }
            }
            // Remove the source tag so it stops interfering with the <img> tag
            source.remove(); 
        });
    }
 
    // Run immediately on page load
    scanDOM();
 
    // Observe the DOM for dynamically loaded content (e.g., Infinite scrolling)
    const observer = new MutationObserver(mutations => {
        mutations.forEach(mutation => {
            if (mutation.addedNodes.length > 0) {
                mutation.addedNodes.forEach(node => {
                    if (node.nodeType === Node.ELEMENT_NODE) {
                        scanDOM(node);
                    }
                });
            }
        });
    });
 
    observer.observe(document.body, { childList: true, subtree: true });
 
})();