diff --git a/ehentai_better_viewer.user.js b/ehentai_better_viewer.user.js
index c1a537d..dccea32 100644
--- a/ehentai_better_viewer.user.js
+++ b/ehentai_better_viewer.user.js
@@ -1,7 +1,7 @@
 // ==UserScript==
 // @name         E-Hentai better viewer
 // @namespace    https://github.com/lifegpc/userscript
-// @version      0.2.2
+// @version      0.3.0
 // @description  Add a viewer to view original picture on website.
 // @author       lifegpc
 // @match        https://*.e-hentai.org/s/*/*
@@ -10,14 +10,82 @@
 // @grant        GM_getResourceText
 // @grant        GM_addElement
 // @grant        GM_addStyle
+// @grant        GM_getValue
+// @grant        GM_setValue
+// @grant        GM_registerMenuCommand
 // @require      https://github.com/lifegpc/viewerjs/raw/main/dist/viewer.min.js
+// @require      https://github.com/emn178/js-sha512/raw/v0.8.0/build/sha512.min.js
+// @require      https://openuserjs.org/src/libs/sizzle/GM_config.js
 // @resource     viewercss https://github.com/lifegpc/viewerjs/raw/main/dist/viewer.min.css
 // @run-at       document-start
 // ==/UserScript==
+GM_config.init({
+    id: 'e-hentai',
+    fields: {
+        enableRedirectAPI: {
+            type: 'checkbox',
+            label: 'Enable redirect api. This need a thirdparty server.',
+            default: false
+        },
+        APIEndpoint: {
+            type: 'hidden'
+        },
+        tempAPIEndpoint: {
+            label: 'The endpoint of the API:',
+            type: 'text',
+            save: false
+        },
+        APISecret: {
+            label: 'The API secret:',
+            type: 'text'
+        },
+        LoadOriginalWhenOpen: {
+            type: 'checkbox',
+            label: 'Load original pictures when opening the viewer modal.',
+            default: false
+        },
+    },
+    events: {
+        init: () => {
+            GM_config.set("tempAPIEndpoint", GM_config.get("APIEndpoint"))
+        },
+        open: () => {
+            GM_config.set("tempAPIEndpoint", GM_config.get("APIEndpoint"))
+        },
+        save: (values) => {
+            console.log(values);
+            if (GM_config.get('enableRedirectAPI')) {
+                if (values.tempAPIEndpoint !== null) {
+                    try {
+                        GM_config.set("APIEndpoint", new URL(values.tempAPIEndpoint).toString());
+                    } catch (e) {
+                        GM_config.set("enableRedirectAPI", false);
+                        console.log(e);
+                    }
+                }
+                if (!GM_config.get("APISecret")) {
+                    GM_config.set("enableRedirectAPI", false);
+                }
+            }
+        }
+    }
+})
+GM_registerMenuCommand("Edit Settings", () => { GM_config.open() }, "e");
 GM_addStyle(GM_getResourceText("viewercss"));
 function indirectEval(script) {
     return eval(`"use strict";${script}`);
 }
+function parse_cookies() {
+    let cookies = document.cookie.split(";");
+    let o = {};
+    for (let c of cookies) {
+        c = c.trim().split("=");
+        let k = c[0];
+        let v = c.slice(1).join("=");
+        o[k] = v;
+    }
+    return o;
+}
 function find_script() {
     let cols = document.getElementsByTagName("script");
     for (let col of cols) {
@@ -26,6 +94,140 @@ function find_script() {
         }
     }
 }
+/**
+ * encodeURIComponent as python's quote_plus behavoir
+ * @param {string} str
+ * @returns
+ */
+function py_quote(str) {
+    let s = encodeURIComponent(str);
+    while (s.includes('%20')) {
+        s = s.replace('%20', '+');
+    }
+    while (s.includes('!')) {
+        s = s.replace('!', '%21');
+    }
+    while (s.includes("'")) {
+        s = s.replace("'", '%27');
+    }
+    while (s.includes('(')) {
+        s = s.replace('(', '%28');
+    }
+    while (s.includes(')')) {
+        s = s.replace(')', '%29');
+    }
+    while (s.includes('*')) {
+        s = s.replace('*', '%2A');
+    }
+    return s;
+}
+class URLParams extends URLSearchParams {
+    toString() {
+        let r = "";
+        for (let p of this.entries()) {
+            if (r.length) r += "&";
+            r += py_quote(p[0]) + "=" + py_quote(p[1]);
+        }
+        return r;
+    }
+}
+/**
+ * 发送GET请求
+ * @param {string} url 网站
+ * @param {Object<string, string>|Array<Array<string>|string>} data 字典
+ * @param {(content: string)=>void} callback 回调函数
+ * @param {()=>void} failedCallback 失败回调函数
+ * @param {Object<string, string>} headers HTTP头部
+ */
+function get(url, data, callback, failedCallback, headers) {
+    var xhr = new XMLHttpRequest();
+    var uri = new URL(url, window.location.href);
+    if (data == undefined);
+    else if (Array.isArray(data)) {
+        for (let i = 0; i < data.length; i++) {
+            var pair = data[i];
+            if (Array.isArray(pair)) {
+                uri.searchParams.append(pair[0], pair.length > 1 ? pair[1] : "");
+            } else if (typeof pair == "string") {
+                uri.searchParams.append(pair, "");
+            }
+        }
+    } else {
+        Object.getOwnPropertyNames(data).forEach((key) => {
+            if (typeof data[key] == "string")
+                uri.searchParams.append(key, data[key]);
+        })
+    }
+    xhr.open("GET", uri.href);
+    if (callback != undefined) xhr.onload = () => {
+        callback(xhr.responseText);
+    };
+    if (failedCallback != undefined) xhr.onerror = failedCallback;
+    if (headers != undefined) {
+        Object.getOwnPropertyNames(headers).forEach((key) => {
+            if (typeof headers[key] == "string")
+                xhr.setRequestHeader(key, headers[key])
+        })
+    }
+    try {
+        xhr.send();
+    } catch (e) {
+        if (failedCallback != undefined) failedCallback();
+    }
+}
+/**
+ * Generate sign for data
+ * @param {Object<string, string | Array<string>>|FormData} data Data
+ * @param {string} secret Secret
+ * @param {(data: string) => string|undefined} hash The hash function
+ * @returns {string}
+ */
+function genGetSign(data, secret, hash) {
+    if (!hash) hash = sha512;
+    /**@type {Array<{k: string, v: string}>} */
+    let arr = [];
+    if (data.constructor.name == "FormData") {
+        for (let pair of data.entries()) {
+            if (typeof pair[1] != "string") continue;
+            arr.push({ k: pair[0], v: pair[1] });
+        }
+    } else {
+        Object.getOwnPropertyNames(data).forEach((key) => {
+            let v = data[key];
+            if (typeof v == "string") arr.push({ k: key, v: v });
+            else if (Array.isArray(v)) {
+                v.forEach((v) => {
+                    if (typeof v == "string") arr.push({ k: key, v: v });
+                })
+            }
+        })
+    }
+    arr.sort((a, b) => {
+        return a.k == b.k ? a.v == b.v ? 0 : a.v > b.v ? 1 : -1 : a.k > b.k ? 1 : -1;
+    })
+    let par = new URLParams();
+    arr.forEach((v) => {
+        par.append(v.k, v.v);
+    })
+    return hash(secret + par.toString());
+}
+function redirect_url(url) {
+    return new Promise((resolve, reject) => {
+        let api = GM_config.get("APIEndpoint");
+        let screct = GM_config.get("APISecret");
+        if (!api || !screct) {
+            reject("Endpoint or screct not found.");
+            return;
+        }
+        let data = {'t': url, 'ar': '0', 'rraj': '1', 'c': JSON.stringify(parse_cookies()), 'r': 'https://e-hentai.org/' };
+        data['sign'] = genGetSign(data, screct);
+        get(api, data, (c) => {
+            resolve(JSON.parse(c)['location']);
+        }, () => {
+            reject("Error");
+        })
+    })
+}
 let base_url = undefined;
 let cur_img = null;
 let cur_viewer = null;
@@ -34,6 +236,8 @@ let api_url = undefined;
 let gid = undefined;
 let showkey = undefined;
 let img_keys = {};
+let original_url = null;
+let redirected_url = null;
 let cur_page = null;
 let total_page = null;
 function get_api_url() {
@@ -104,6 +308,10 @@ async function loadPage(page) {
     let xhr = await api_call({ method: "showpage", gid, page, imgkey, showkey });
     let a = JSON.parse(xhr.responseText);
     if (cur_viewer) cur_viewer.destroy();
+    cur_img = null;
+    cur_viewer = null;
+    original_url = null;
+    redirected_url = null;
     document.getElementById("i1").style.width = a.x + "px";
     document.getElementById("i2").innerHTML = a.n + a.i;
     document.getElementById("i3").innerHTML = a.i3;
@@ -126,6 +334,20 @@ function replaceLink(a) {
     na.addEventListener("click", () => { loadPage(num); });
     a.replaceWith(na);
 }
+async function loadOriginalImage() {
+    let url = original_url;
+    if (!url) return false;
+    if (GM_config.get("enableRedirectAPI")) {
+        if (redirected_url) {
+            url = redirected_url;
+        } else {
+            redirected_url = await redirect_url(url);
+            url = redirected_url;
+        }
+    }
+    cur_img.src = url;
+    return true;
+}
 let load = () => {
     let img = document.getElementById("img");
     if (img == null) {
@@ -150,13 +372,15 @@ let load = () => {
     let original = document.querySelector("#i7>a");
     if (original != null) {
         let ourl = original.href;
-        console.log(ourl);
-        options.url = ourl;
+        original_url = ourl;
     }
     console.log(options);
     let viewer = new Viewer(img, options);
     let click = async () => {
         img.removeEventListener("click", click);
+        if (GM_config.get("LoadOriginalWhenOpen")) {
+            await loadOriginalImage();
+        }
         await viewer.init();
         console.log("Inited complete");
         await viewer.show();