修复连续改图变糊：历史图优先原始上传并提升默认清晰度

app/(chat)/api/chat/route.ts

@@ -956,52 +956,81 @@ export async function POST(request: Request) {
         if (!hasImage && smartAutoHistoryMessagesFromDb.length > 0) {
           console.log("[Smart Auto Mode] 🔍 No image in current message, auto-searching history...");
 
-          // 从历史消息中倒序查找最近一轮包含图片的消息
+          const explicitFollowLatestResult = /(上一张|上一轮|刚生成|最新生成|这个结果|该结果|按这个结果|继续在这张|基于这张结果|延续上一次结果)/i.test(
-          // 收集该消息中的所有图片（支持多图融合编辑）
+            textContent
+          );
+
+          const latestAssistantImages: string[] = [];
+          const latestUserImages: string[] = [];
+          const pushUniqueUrl = (bucket: string[], maybeUrl?: string) => {
+            if (!maybeUrl || typeof maybeUrl !== "string") return;
+            const normalized = maybeUrl.trim();
+            if (!/^https?:\/\//i.test(normalized)) return;
+            if (!bucket.includes(normalized)) {
+              bucket.push(normalized);
+            }
+          };
+
+          // 从历史消息中倒序查找最近的“AI生成图”和“用户上传图”
           for (let i = smartAutoHistoryMessagesFromDb.length - 1; i >= 0; i--) {
             const msg = smartAutoHistoryMessagesFromDb[i];
             const parts = msg.parts as any[];
 
             if (!parts) continue;
 
-            // 查找AI生成的图片（从Markdown中提取所有图片）
+            if (msg.role === "assistant" && latestAssistantImages.length === 0) {
-            if (msg.role === "assistant") {
               for (const part of parts) {
                 if (part.type === "text" && part.text) {
-                  // 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)) {
+                    pushUniqueUrl(latestAssistantImages, parsedUrl);
-                      smartAutoHistoryImages.push(parsedUrl);
-                    }
                   }
                 }
               }
-              // 如果在这条assistant消息中找到了图片，就停止搜索（使用最近一轮的结果）
-              if (smartAutoHistoryImages.length > 0) {
-                console.log("[Smart Auto Mode] 🖼️ Found AI-generated images:", smartAutoHistoryImages.length);
-                break;
-              }
             }
 
-            // 查找用户上传的图片（收集该消息中的所有图片）
+            if (msg.role === "user" && latestUserImages.length === 0) {
-            if (msg.role === "user" && smartAutoHistoryImages.length === 0) {
               for (const part of parts) {
                 if ((part.type === "file" || part.type === "image") && part.url) {
-                  if (!smartAutoHistoryImages.includes(part.url)) {
+                  pushUniqueUrl(latestUserImages, part.url);
-                    smartAutoHistoryImages.push(part.url);
+                }
+                if (part.type === "image_url" && part.image_url?.url) {
+                  pushUniqueUrl(latestUserImages, part.image_url.url);
+                }
+                if (part.type === "text" && part.text) {
+                  const parsedImageUrls = extractOriginalImageUrlsFromText(part.text);
+                  for (const parsedUrl of parsedImageUrls) {
+                    pushUniqueUrl(latestUserImages, parsedUrl);
                   }
                 }
               }
-              // 如果在这条user消息中找到了图片，就停止搜索
+            }
-              if (smartAutoHistoryImages.length > 0) {
+
-                console.log("[Smart Auto Mode] 🖼️ Found user-uploaded images:", smartAutoHistoryImages.length);
+            if (latestAssistantImages.length > 0 && latestUserImages.length > 0) {
-                break;
+              break;
-              }
             }
           }
 
-          // 如果找到了历史图片，标记为有图片
+          if (explicitFollowLatestResult && latestAssistantImages.length > 0) {
+            smartAutoHistoryImages = latestAssistantImages.slice(0, 4);
+            console.log(
+              "[Smart Auto Mode] 🖼️ Using latest generated image(s) by explicit instruction:",
+              smartAutoHistoryImages.length
+            );
+          } else if (latestUserImages.length > 0) {
+            smartAutoHistoryImages = latestUserImages.slice(0, 4);
+            console.log(
+              "[Smart Auto Mode] 🖼️ Using latest user-uploaded image(s) to avoid iterative blur:",
+              smartAutoHistoryImages.length
+            );
+          } else if (latestAssistantImages.length > 0) {
+            smartAutoHistoryImages = latestAssistantImages.slice(0, 4);
+            console.log(
+              "[Smart Auto Mode] 🖼️ Fallback to latest generated image(s):",
+              smartAutoHistoryImages.length
+            );
+          }
+
           if (smartAutoHistoryImages.length > 0) {
             hasImage = true;
             imageUrls = smartAutoHistoryImages;
@@ -1201,6 +1230,11 @@ export async function POST(request: Request) {
           hasUserCustomSettings: hasUserCustomImageParams,
         })
       : requestBody.imageParams;
+    const defaultImageQualityParams = {
+      aspectRatio: "auto",
+      imageSize: smartAutoDetectedIntent === "image_edit" ? "4K" : "2K",
+      imageCount: 1,
+    } as const;
 
     if (shouldApplyAgentImageParams) {
       console.log("[Smart Auto Mode] 🎯 Effective image params:", {
@@ -1564,7 +1598,11 @@ export async function POST(request: Request) {
             // 调用 doGenerate 获取图片（如果是备用模型，传入 overrideModelId）
             const result = await (languageModel as any).doGenerate({
               messages: modelMessages,
-              imageParams: effectiveImageParams || { aspectRatio: "auto", imageSize: "2K" },
+              imageParams:
+                effectiveImageParams || {
+                  aspectRatio: defaultImageQualityParams.aspectRatio,
+                  imageSize: defaultImageQualityParams.imageSize,
+                },
               overrideModelId: isRetry ? modelIdToUse : undefined, // 🆕 使用备用模型 ID
             });
             
@@ -1930,7 +1968,12 @@ export async function POST(request: Request) {
               // 调用 doGenerate 获取图片，传递模型显示名称
               const result = await (languageModel as any).doGenerate({
                 messages: modelMessages,
-                imageParams: effectiveImageParams || { aspectRatio: "auto", imageSize: "2K", imageCount: 1 },
+                imageParams:
+                  effectiveImageParams || {
+                    aspectRatio: defaultImageQualityParams.aspectRatio,
+                    imageSize: defaultImageQualityParams.imageSize,
+                    imageCount: defaultImageQualityParams.imageCount,
+                  },
                 modelDisplayName, // 🆕 传递模型显示名称
                 overrideModelId: isRetry ? modelIdToUse : undefined,
               });
@@ -2028,7 +2071,12 @@ export async function POST(request: Request) {
 
                     const candidateResult = await (candidateLanguageModel as any).doGenerate({
                       messages: candidateMessages,
-                      imageParams: effectiveImageParams || { aspectRatio: "auto", imageSize: "2K", imageCount: 1 },
+                      imageParams:
+                        effectiveImageParams || {
+                          aspectRatio: defaultImageQualityParams.aspectRatio,
+                          imageSize: defaultImageQualityParams.imageSize,
+                          imageCount: defaultImageQualityParams.imageCount,
+                        },
                       modelDisplayName: candidate.model.displayName,
                       overrideModelId: candidate.model.modelId,
                     });
@@ -2274,7 +2322,12 @@ export async function POST(request: Request) {
             const tryGenerateImage = async (modelIdToUse: string, isRetry: boolean) => {
               const result = await (languageModel as any).doGenerate({
                 messages: modelMessages,
-                imageParams: effectiveImageParams || { aspectRatio: "auto", imageSize: "2K", imageCount: 1 },
+                imageParams:
+                  effectiveImageParams || {
+                    aspectRatio: defaultImageQualityParams.aspectRatio,
+                    imageSize: defaultImageQualityParams.imageSize,
+                    imageCount: defaultImageQualityParams.imageCount,
+                  },
                 overrideModelId: isRetry ? modelIdToUse : undefined,
               });
               if (result?.finishReason === "error") {
@@ -2366,7 +2419,12 @@ export async function POST(request: Request) {
 
                     const candidateResult = await (candidateLanguageModel as any).doGenerate({
                       messages: candidateMessages,
-                      imageParams: effectiveImageParams || { aspectRatio: "auto", imageSize: "2K", imageCount: 1 },
+                      imageParams:
+                        effectiveImageParams || {
+                          aspectRatio: defaultImageQualityParams.aspectRatio,
+                          imageSize: defaultImageQualityParams.imageSize,
+                          imageCount: defaultImageQualityParams.imageCount,
+                        },
                       modelDisplayName: candidate.model.displayName,
                       overrideModelId: candidate.model.modelId,
                     });

components/image-preview.tsx

@@ -171,7 +171,7 @@ export function ImagePreview({
   };
 
   const { thumbnail, original, maxWidth, is4K } = parseImageUrls();
-  const preferOriginalForPreview = maxWidth >= 380 && original && original !== thumbnail;
+  const preferOriginalForPreview = Boolean(original && original !== thumbnail);
   const previewSrc = preferOriginalForPreview ? original : thumbnail;
   const previewSrcSet = original
     ? `${thumbnail} 1x, ${original} 2x`