diff --git a/app/(chat)/api/chat/_lib/detail-replacement.ts b/app/(chat)/api/chat/_lib/detail-replacement.ts
index b5e458e8b..21155b94f 100644
--- a/app/(chat)/api/chat/_lib/detail-replacement.ts
+++ b/app/(chat)/api/chat/_lib/detail-replacement.ts
@@ -187,6 +187,7 @@ export async function normalizeReplacementResultImage(params: {
   generatedThumbnailUrl?: string;
   referenceImageUrl: string;
   referenceGeometry?: ReplacementReferenceGeometry | null;
+  scenePlan?: ReplacementScenePlan | null;
   uploadPrefix: string;
 }): Promise<{
   originalUrl: string;
@@ -235,13 +236,23 @@ export async function normalizeReplacementResultImage(params: {
   const shouldCropTallComposite =
     Boolean(targetAspectRatio && generatedAspectRatio) &&
     Number(generatedAspectRatio) < Number(targetAspectRatio) * 0.78;
+  const shouldPreserveFullGeneratedCanvas =
+    params.scenePlan?.whiteBackgroundLikely === true ||
+    params.scenePlan?.textPolicy === "lock" ||
+    params.scenePlan?.generationRoute === "copy_locked_regenerate" ||
+    params.scenePlan?.generationRoute === "layout_preserve_replace";
+  const resizeFit = shouldCropTallComposite
+    ? "cover"
+    : shouldPreserveFullGeneratedCanvas
+      ? "contain"
+      : "cover";
   const normalizedBuffer =
     targetWidth && targetHeight
       ? await imagePipeline
           .resize(targetWidth, targetHeight, {
-            // Wide outputs need containment to avoid cropping edge text; overly tall outputs
-            // usually mean the model stacked two page variants, so crop to the top page.
-            fit: shouldCropTallComposite ? "cover" : "contain",
+            // Layout-locked copy pages keep containment to protect edge text. Scene pages
+            // fill the target frame so a wrong model aspect does not become a white panel.
+            fit: resizeFit,
             position: shouldCropTallComposite ? "top" : "centre",
             background: { r: 255, g: 255, b: 255, alpha: 1 },
             withoutEnlargement: false,
diff --git a/app/(chat)/api/chat/route.ts b/app/(chat)/api/chat/route.ts
index 4a2d054c9..68e97de60 100644
--- a/app/(chat)/api/chat/route.ts
+++ b/app/(chat)/api/chat/route.ts
@@ -3530,6 +3530,7 @@ export async function POST(request: Request) {
                     generatedThumbnailUrl: firstImage.thumbnailUrl,
                     referenceImageUrl: reference.imageUrl,
                     referenceGeometry,
+                    scenePlan: replacementExecutionPlan.scenePlan,
                     uploadPrefix: "agent-detail-replacement",
                   });
                   finalImage = {
@@ -4333,6 +4334,7 @@ export async function POST(request: Request) {
                       generatedThumbnailUrl: firstImage.thumbnailUrl,
                       referenceImageUrl: reference.imageUrl,
                       referenceGeometry,
+                      scenePlan: replacementExecutionPlan.scenePlan,
                       uploadPrefix: isDetailReplacementPreset
                         ? "agent-detail-replacement"
                         : "agent-sku-replacement",
diff --git a/components/agents/AgentGenerationWorkspaceDarkV2.tsx b/components/agents/AgentGenerationWorkspaceDarkV2.tsx
index d2c1b8f91..a14d89b37 100644
--- a/components/agents/AgentGenerationWorkspaceDarkV2.tsx
+++ b/components/agents/AgentGenerationWorkspaceDarkV2.tsx
@@ -6685,7 +6685,7 @@ export function AgentGenerationWorkspaceDarkV2({
                           )}
                           onClick={() => setActiveDetailReferenceCardId(card.id)}
                         >
-                          <div className="relative aspect-[790/1300] overflow-hidden bg-white/95">
+                          <div className="relative min-h-[220px] overflow-hidden bg-white/95">
                             <div className="absolute right-3 top-3 z-10 flex flex-col items-end gap-2">
                               <button
                                 type="button"
@@ -6718,7 +6718,7 @@ export function AgentGenerationWorkspaceDarkV2({
                               <AgentPreviewImage
                                 src={card.imageUrl}
                                 alt={card.label}
-                                className="h-full w-full object-contain"
+                                className="block h-auto w-full"
                                 previewWidth={720}
                                 previewQuality={76}
                                 onError={(event) =>
@@ -6808,11 +6808,11 @@ export function AgentGenerationWorkspaceDarkV2({
                           )}
                         >
                           {hasResult ? (
-                            <div className="relative aspect-[790/1300] overflow-hidden bg-white/95">
+                            <div className="relative min-h-[220px] overflow-hidden bg-white/95">
                               <AgentPreviewImage
                                 src={card.resultUrl!}
                                 alt={`结果图 ${card.index + 1}`}
-                                className="h-full w-full cursor-zoom-in object-contain"
+                                className="block h-auto w-full cursor-zoom-in"
                                 previewWidth={720}
                                 previewQuality={78}
                                 onError={(event) =>