diff --git a/app/(chat)/api/chat/route.ts b/app/(chat)/api/chat/route.ts
index d1d1a72..27964ad 100644
--- a/app/(chat)/api/chat/route.ts
+++ b/app/(chat)/api/chat/route.ts
@@ -367,6 +367,86 @@ async function convertMessagesWithImages(messages: ChatMessage[], providerType:
   return convertedMessages;
 }
 
+function parseImageAltMetadata(altText: string, thumbnailUrl: string): {
+  originalUrl: string;
+  imageSize: string;
+} {
+  let originalUrl = thumbnailUrl;
+  let imageSize = "2K";
+
+  // 格式1: thumb|||originalUrl|||size (新格式)
+  if (altText.includes("thumb|||")) {
+    const content = altText.substring(altText.indexOf("thumb|||") + 8);
+    const parts = content.split("|||");
+    originalUrl = parts[0] || thumbnailUrl;
+    imageSize = parts[1] || "2K";
+  }
+  // 格式2: thumb$$originalUrl$$size (中间格式，可能被 LaTeX 解析器破坏)
+  else if (altText.includes("thumb$$")) {
+    const content = altText.substring(altText.indexOf("thumb$$") + 7);
+    const parts = content.split("$$");
+    originalUrl = parts[0] || thumbnailUrl;
+    imageSize = parts[1] || "2K";
+  }
+  // 格式3: thumb|originalUrl|size (旧格式)
+  else if (altText.includes("thumb|")) {
+    const content = altText.substring(altText.indexOf("thumb|") + 6);
+    const parts = content.split("|");
+    originalUrl = parts[0] || thumbnailUrl;
+    imageSize = parts[1] || "2K";
+  }
+
+  // 回退策略：从缩略图 URL 推断原图 URL
+  if (originalUrl === thumbnailUrl) {
+    if (thumbnailUrl.includes("gemini-thumb-")) {
+      originalUrl = thumbnailUrl.replace("gemini-thumb-", "gemini-orig-");
+    } else if (thumbnailUrl.includes("openai-thumb-")) {
+      originalUrl = thumbnailUrl.replace("openai-thumb-", "openai-orig-");
+    } else if (thumbnailUrl.includes("volcano-thumb-")) {
+      originalUrl = thumbnailUrl.replace("volcano-thumb-", "volcano-orig-");
+    } else if (thumbnailUrl.includes("alibaba-image-thumb-")) {
+      originalUrl = thumbnailUrl.replace("alibaba-image-thumb-", "alibaba-image-orig-");
+    } else if (thumbnailUrl.includes("ruxa-image-thumb-")) {
+      originalUrl = thumbnailUrl.replace("ruxa-image-thumb-", "ruxa-image-orig-");
+    }
+  }
+
+  return { originalUrl, imageSize };
+}
+
+function extractOriginalImageUrlsFromText(text: string): string[] {
+  const imageRegex = /!\[([^\]]*)\]\((https?:\/\/[^\s)]+)\)/g;
+  const imageUrls: string[] = [];
+  const added = new Set<string>();
+  let hasMarkdownImages = false;
+  let match: RegExpExecArray | null;
+
+  while ((match = imageRegex.exec(text)) !== null) {
+    hasMarkdownImages = true;
+    const altText = match[1] || "";
+    const thumbnailUrl = match[2];
+    const { originalUrl } = parseImageAltMetadata(altText, thumbnailUrl);
+    const finalUrl = originalUrl || thumbnailUrl;
+    if (finalUrl && /^https?:\/\//i.test(finalUrl) && !added.has(finalUrl)) {
+      added.add(finalUrl);
+      imageUrls.push(finalUrl);
+    }
+  }
+
+  if (!hasMarkdownImages) {
+    const urlRegex = /https?:\/\/[^\s"'<>]+\.(?:jpg|jpeg|png|gif|webp|bmp|svg)(?:\?[^\s"'<>]*)?/gi;
+    const matchedUrls = text.match(urlRegex) || [];
+    for (const url of matchedUrls) {
+      if (!added.has(url)) {
+        added.add(url);
+        imageUrls.push(url);
+      }
+    }
+  }
+
+  return imageUrls;
+}
+
 /**
  * 解析生图 Markdown 并保存图片记录到数据库
  * 支持三种格式：thumb|||url|||size、thumb$$url$$size、thumb|url|size
@@ -386,48 +466,7 @@ async function saveGeneratedImages(
   for (const match of matches) {
     const altText = match[1] || "";
     const thumbnailUrl = match[2];
-    let originalUrl = thumbnailUrl;
-    let imageSize = "2K";
-
-    // 解析 alt 中的原图 URL 和尺寸
-    // 格式1: thumb|||originalUrl|||size (新格式)
-    if (altText.includes("thumb|||")) {
-      const content = altText.substring(altText.indexOf("thumb|||") + 8);
-      const parts = content.split("|||");
-      originalUrl = parts[0] || thumbnailUrl;
-      imageSize = parts[1] || "2K";
-    }
-    // 格式2: thumb$$originalUrl$$size (中间格式，可能被 LaTeX 解析器破坏)
-    else if (altText.includes("thumb$$")) {
-      const content = altText.substring(altText.indexOf("thumb$$") + 7);
-      const parts = content.split("$$");
-      originalUrl = parts[0] || thumbnailUrl;
-      imageSize = parts[1] || "2K";
-    }
-    // 格式3: thumb|originalUrl|size (旧格式)
-    else if (altText.includes("thumb|")) {
-      const content = altText.substring(altText.indexOf("thumb|") + 6);
-      const parts = content.split("|");
-      originalUrl = parts[0] || thumbnailUrl;
-      imageSize = parts[1] || "2K";
-    }
-
-    // 回退策略：从缩略图 URL 推断原图 URL
-    if (originalUrl === thumbnailUrl) {
-      if (thumbnailUrl.includes("gemini-thumb-")) {
-        originalUrl = thumbnailUrl.replace("gemini-thumb-", "gemini-orig-");
-      } else if (thumbnailUrl.includes("openai-thumb-")) {
-        originalUrl = thumbnailUrl.replace("openai-thumb-", "openai-orig-");
-      } else if (thumbnailUrl.includes("volcano-thumb-")) {
-        originalUrl = thumbnailUrl.replace("volcano-thumb-", "volcano-orig-");
-      } else if (thumbnailUrl.includes("alibaba-image-thumb-")) {
-        // 🆕 阿里生图模型
-        originalUrl = thumbnailUrl.replace("alibaba-image-thumb-", "alibaba-image-orig-");
-      } else if (thumbnailUrl.includes("ruxa-image-thumb-")) {
-        // 🆕 RUXA 生图模型
-        originalUrl = thumbnailUrl.replace("ruxa-image-thumb-", "ruxa-image-orig-");
-      }
-    }
+    const { originalUrl, imageSize } = parseImageAltMetadata(altText, thumbnailUrl);
 
     try {
       await db.insert(generatedImage).values({
@@ -595,11 +634,11 @@ export async function POST(request: Request) {
             if (msg.role === "assistant") {
               for (const part of parts) {
                 if (part.type === "text" && part.text) {
-                  // 匹配所有Markdown图片格式: ![alt](url)
-                  const imgMatches = part.text.matchAll(/!\[.*?\]\((https?:\/\/[^\s)]+)\)/g);
-                  for (const match of imgMatches) {
-                    if (match[1] && !smartAutoHistoryImages.includes(match[1])) {
-                      smartAutoHistoryImages.push(match[1]);
+                  // 从 markdown 中优先提取原图 URL，避免把缩略图当作下一轮输入导致画质下降
+                  const parsedImageUrls = extractOriginalImageUrlsFromText(part.text);
+                  for (const parsedUrl of parsedImageUrls) {
+                    if (!smartAutoHistoryImages.includes(parsedUrl)) {
+                      smartAutoHistoryImages.push(parsedUrl);
                     }
                   }
                 }