diff --git a/package.json b/package.json
index 14eda1b..9666a8f 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "packageManager": "pnpm@11.22.0",
   "scripts": {
     "dev": "next dev",
+    "cache-images": "node scripts/cache-images.mjs",
     "build": "next build",
     "start": "next start",
     "lint": "eslint"
diff --git a/scripts/cache-images.mjs b/scripts/cache-images.mjs
new file mode 100644
index 0000000..19be9be
--- /dev/null
+++ b/scripts/cache-images.mjs
@@ -0,0 +1,84 @@
+import { createHash } from "node:crypto";
+import { mkdir, readFile, readdir, writeFile } from "node:fs/promises";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const contentRoot = path.join(root, "src", "data");
+const outputRoot = path.join(root, "public", "media", "news");
+const manifestPath = path.join(root, "src", "lib", "image-map.generated.ts");
+const remoteUrlPattern = /https?:\/\/[^\s)>'"]+/g;
+const imageExtensionPattern = /\.(?:avif|gif|jpe?g|png|svg|webp)(?:[?#].*)?$/i;
+
+async function collectMarkdownFiles(directory) {
+  const entries = await readdir(directory, { withFileTypes: true });
+  const files = [];
+
+  for (const entry of entries) {
+    const entryPath = path.join(directory, entry.name);
+    if (entry.isDirectory()) files.push(...await collectMarkdownFiles(entryPath));
+    else if (entry.isFile() && entry.name.endsWith(".md")) files.push(entryPath);
+  }
+
+  return files;
+}
+
+function cleanUrl(value) {
+  return value.replace(/[.,;:!?]+$/, "");
+}
+
+function getExtension(url, contentType) {
+  const pathname = new URL(url).pathname;
+  const extension = path.extname(pathname).toLowerCase();
+  if (extension && imageExtensionPattern.test(pathname)) return extension;
+  const typeExtension = contentType.split("/")[1]?.split(";")[0]?.toLowerCase();
+  return typeExtension === "jpeg" ? ".jpg" : `.${typeExtension || "bin"}`;
+}
+
+async function downloadImage(url) {
+  const response = await fetch(url, {
+    redirect: "follow",
+    signal: AbortSignal.timeout(15000),
+  });
+  if (!response.ok) throw new Error(`${response.status} ${response.statusText}`);
+
+  const contentType = response.headers.get("content-type") || "application/octet-stream";
+  if (!contentType.startsWith("image/")) throw new Error(`unexpected content type ${contentType}`);
+
+  const bytes = Buffer.from(await response.arrayBuffer());
+  const hash = createHash("sha256").update(bytes).digest("hex").slice(0, 16);
+  const fileName = `${hash}${getExtension(url, contentType)}`;
+  await writeFile(path.join(outputRoot, fileName), bytes);
+  return `/media/news/${fileName}`;
+}
+
+const markdownFiles = await collectMarkdownFiles(contentRoot);
+const remoteUrls = new Set();
+for (const filePath of markdownFiles) {
+  const content = await readFile(filePath, "utf8");
+  for (const match of content.matchAll(remoteUrlPattern)) {
+    const url = cleanUrl(match[0]);
+    if (imageExtensionPattern.test(url)) remoteUrls.add(url);
+  }
+}
+
+await mkdir(outputRoot, { recursive: true });
+const imageMap = {};
+let failed = 0;
+const urls = [...remoteUrls];
+const concurrency = 8;
+for (let index = 0; index < urls.length; index += concurrency) {
+  const batch = urls.slice(index, index + concurrency);
+  await Promise.all(batch.map(async (url) => {
+    try {
+      imageMap[url] = await downloadImage(url);
+    } catch (error) {
+      failed += 1;
+      console.warn(`[cache-images] skipped ${url}: ${error.message}`);
+    }
+  }));
+}
+
+const generated = `// Generated by scripts/cache-images.mjs. Do not edit.\nexport const imageMap: Record<string, string> = ${JSON.stringify(imageMap, null, 2)};\n`;
+await writeFile(manifestPath, generated, "utf8");
+console.log(`[cache-images] cached ${Object.keys(imageMap).length}/${remoteUrls.size} images${failed ? `; ${failed} failed` : ""}`);
\ No newline at end of file
diff --git a/src/data/news/index.ts b/src/data/news/index.ts
index 7b1bc37..7762e0b 100644
--- a/src/data/news/index.ts
+++ b/src/data/news/index.ts
@@ -2,6 +2,7 @@ import fs from "fs/promises";
 import path from "path";
 import type { Locale } from "@/lib/i18n";
 import { markdownToHtml } from "@/lib/markdown";
+import { imageMap } from "@/lib/image-map.generated";
 
 export type NewsItem = {
   id: string;
@@ -71,7 +72,8 @@ function normalizeNewsItem(fileName: string, raw: NewsFrontmatter, body: string)
   const date = raw.date?.trim() || "未注明日期";
   const category = (Array.isArray(raw.category) ? raw.category[0] : raw.category)?.trim() || "未分类";
   const tags = raw.tags ?? [];
-  const cover = raw.cover?.trim() || DEFAULT_NEWS_COVER;
+  const coverSource = raw.cover?.trim() || DEFAULT_NEWS_COVER;
+  const cover = imageMap[coverSource] ?? coverSource;
   const slug = raw.slug?.trim() || fileName.replace(/\.md$/i, "");
 
   if (!title) {
diff --git a/src/lib/image-map.generated.ts b/src/lib/image-map.generated.ts
new file mode 100644
index 0000000..05414d9
--- /dev/null
+++ b/src/lib/image-map.generated.ts
@@ -0,0 +1,35 @@
+// Generated by scripts/cache-images.mjs. Do not edit.
+export const imageMap: Record<string, string> = {
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137fa6a70de.jpg": "/media/news/897d764a65897170.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137fb192614.jpg": "/media/news/852dd5b369bf377d.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137fffd1a19.png": "/media/news/7ae2b8fba574195b.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137ff194540.png": "/media/news/7f7c61ff4b22140d.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137ffd40a9c.png": "/media/news/faa9264b9cbf052b.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137f9cf1f48.png": "/media/news/8ecb7a6b90f318e0.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/68137ffa67186.png": "/media/news/acd56aafe8b41f05.png",
+  "https://s21.ax1x.com/2024/09/20/pAMSLRJ.png": "/media/news/02882b262ac53ec2.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/6813812298936.png": "/media/news/d699056d1f6db7a2.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681381518e5b7.png": "/media/news/e1ff2fb0e0402a83.png",
+  "https://r2-image.kivotosrailway.com/2025/04/02/67ece50d760f8.png": "/media/news/625c4eff0e6c3206.png",
+  "https://r2-image.kivotosrailway.com/2025/04/02/67ece40c0bc76.png": "/media/news/8419859923ddbe8f.png",
+  "https://r2-image.kivotosrailway.com/2025/04/02/67ecdfbf7e858.png": "/media/news/26f4a1313bbcf030.png",
+  "https://r2-image.kivotosrailway.com/2025/04/02/67ecf1b42ef19.png": "/media/news/f51e4ded0e8d6b85.png",
+  "https://r2-image.kivotosrailway.com/2025/01/07/677d16a21da4c.png": "/media/news/9e3cba51761fc108.png",
+  "https://r2-image.kivotosrailway.com/2025/01/14/6785481e73832.png": "/media/news/694e30e5ce74b863.png",
+  "https://r2-image.kivotosrailway.com/2025/02/17/67b20e14d2e42.png": "/media/news/c3ab207db385ddd7.png",
+  "https://image.kivotosrailway.com/uploads/696b7416b1764.jpg": "/media/news/f1e7be44f3b76abc.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/14/682374369d005.png": "/media/news/d67395b9a4d20687.png",
+  "https://r2-image.kivotosrailway.com/2025/05/13/68236919b3ebe.png": "/media/news/0dce62106c0c48a5.png",
+  "https://r2-image.kivotosrailway.com/2025/05/14/6823735cea4de.png": "/media/news/06b8cffc367a6f28.png",
+  "https://s21.ax1x.com/2024/09/20/pAMS0KI.png": "/media/news/c6e4e344e54d4976.png",
+  "https://s21.ax1x.com/2024/09/20/pAMSWxs.png": "/media/news/5149b301e12e850b.png",
+  "https://r2-image.kivotosrailway.com/2025/12/14/693ec8c79b4b8.jpg": "/media/news/3a2bc283672922bc.jpg",
+  "https://r2-image.kivotosrailway.com/2025/12/14/693ec8d313ba2.jpg": "/media/news/77bd04054f6a7224.jpg",
+  "https://r2-image.kivotosrailway.com/2025/12/14/693e5bbe608e5.jpg": "/media/news/99e9760bf7b5f31a.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681396eb28788.jpg": "/media/news/17c8d9be981d42ea.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681396fd3a792.jpg": "/media/news/cd0c5383ca66c6b2.jpg",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681396f661df5.jpg": "/media/news/d245b5b6ea4f98d5.jpg",
+  "https://s21.ax1x.com/2024/12/19/pAO8xoT.png": "/media/news/09f416760a398ccd.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681398635f9b2.png": "/media/news/378bea798cf7c855.png",
+  "https://r2-image.kivotosrailway.com/2025/05/01/681398634fbc4.png": "/media/news/378bea798cf7c855.png"
+};
diff --git a/src/lib/markdown.ts b/src/lib/markdown.ts
index a63221a..1991a42 100644
--- a/src/lib/markdown.ts
+++ b/src/lib/markdown.ts
@@ -1,5 +1,7 @@
 import { marked } from "marked";
+import { imageMap } from "@/lib/image-map.generated";
 
 export function markdownToHtml(markdown: string): string {
-  return marked.parse(markdown, { gfm: true, breaks: false }) as string;
+  const localizedMarkdown = markdown.replace(/https?:\/\/[^\s)>'"]+/g, (url) => imageMap[url.replace(/[.,;:!?]+$/, "")] ?? url);
+  return marked.parse(localizedMarkdown, { gfm: true, breaks: false }) as string;
 }
\ No newline at end of file