diff --git a/api/chat_routes.py b/api/chat_routes.py
index 3ee13c2..2a9e198 100644
--- a/api/chat_routes.py
+++ b/api/chat_routes.py
@@ -352,7 +352,11 @@ def _order_text_contexts_for_prompt(contexts: List[Dict], query: str, max_chunks
                 and (c.get('meta', {}).get('source', ''), c.get('meta', {}).get('section', '') or c.get('meta', {}).get('section_path', '')) in passing_sections
             )
         ]
-        chart_contexts = [c for c in chart_contexts if c.get('score', 0) >= min_score]
+        # 图片/图表切片：CrossEncoder 对图片描述评分系统性偏低（0.002-0.08 vs 文本 0.3-0.9），
+        # 使用更宽松的阈值（min_score * 0.5），避免被误过滤。
+        # 实际内容相关性由 select_images 独立评分保证，此处仅做基础过滤。
+        _chart_floor = min_score * 0.5
+        chart_contexts = [c for c in chart_contexts if c.get('score', 0) >= _chart_floor]
 
     # 合并：文本切片优先，图表切片补充
     # 限制图表切片数量，避免过多
@@ -2752,7 +2756,7 @@ def rag():
 
             # 调试事件：图片选择详情
             if IS_DEV:
-                yield f"data: {json.dumps({'type': 'images_selected', 'data': {'total_scored': len([c for c in contexts if c.get('meta',{}).get('chunk_type') in ('image','chart','table')]), 'selected_count': len(selected_images), 'images': [{'source': img.get('source',''), 'page': img.get('page',0), 'score': round(img.get('_image_boost', 1.0), 2)} for img in selected_images]}}, ensure_ascii=False)}\n\n"
+                yield f"data: {json.dumps({'type': 'images_selected', 'data': {'total_scored': len([c for c in contexts if c.get('meta',{}).get('chunk_type') in ('image','chart','table')]), 'selected_count': len(selected_images), 'images': [{'source': img.get('source',''), 'page': img.get('page',0), 'score': round(img.get('_image_boost', 1.0), 2), 'chunk_id': img.get('chunk_id',''), 'actual_score': round(img.get('score',0), 2), 'id': img.get('id',''), 'desc_preview': (img.get('full_description','') or img.get('description',''))[:60]} for img in selected_images]}}, ensure_ascii=False)}\n\n"
 
             # 4. 构建 prompt（Phase 6：LLM 图片感知）
             # Bug 1 修复：文本切片用于 top 5 名额竞争，图片描述不参与竞争
@@ -2854,8 +2858,53 @@ def rag():
                     # 添加指令让 LLM 介绍图片
                     context_text += "\n\n【回答要求】回答时请简要介绍每张图片的内容和用途。"
 
+            # P0 安全网：确保 select_images 选中的图片描述一定出现在 LLM context 中
+            # 场景：chart_contexts 被 min_score 过滤、_build_context_with_budget 截断、
+            # 或其他过滤逻辑意外排除时，selected_images 仍能提供描述
+            if selected_images and '【相关图片信息】' not in context_text:
+                # 现有注入代码未执行（selected_images 为空时不会进入），补注入
+                image_descriptions = []
+                for i, img in enumerate(selected_images, 1):
+                    full_desc = img.get('full_description', '') or img.get('description', '')
+                    if full_desc and len(full_desc.strip()) >= 5:
+                        img_source = img.get('source', '')
+                        img_page = img.get('page', '')
+                        source_info = f"（来源：{img_source} 第{img_page}页）" if img_source and img_page else ""
+                        image_descriptions.append(f"【图片{i}】{full_desc}{source_info}")
+                if image_descriptions:
+                    context_text += "\n\n【相关图片信息】\n" + "\n\n".join(image_descriptions)
+                    context_text += "\n\n【回答要求】回答时请简要介绍每张图片的内容和用途。"
+            elif selected_images:
+                # 已有【相关图片信息】，检查是否有遗漏（被过滤但 select_images 选中的图片）
+                _existing_desc_ids = set()
+                for img in selected_images:
+                    img_id = img.get('id', '')
+                    if img_id and img_id in context_text:
+                        _existing_desc_ids.add(img_id)
+                _missing = [img for img in selected_images if img.get('id', '') not in _existing_desc_ids]
+                if _missing:
+                    _missing_descs = []
+                    _start_idx = len(selected_images) - len(_missing) + 1
+                    for i, img in enumerate(_missing, _start_idx):
+                        full_desc = img.get('full_description', '') or img.get('description', '')
+                        if full_desc and len(full_desc.strip()) >= 5:
+                            img_source = img.get('source', '')
+                            img_page = img.get('page', '')
+                            source_info = f"（来源：{img_source} 第{img_page}页）" if img_source and img_page else ""
+                            _missing_descs.append(f"【图片{i}】{full_desc}{source_info}")
+                    if _missing_descs:
+                        context_text += "\n\n" + "\n\n".join(_missing_descs)
+
             enhanced_context = context_text
 
+            # P0 日志：图片描述注入完整性检查
+            if selected_images and IS_DEV:
+                _img_ids_in_ctx = {img.get('id', '') for img in selected_images if img.get('id', '') and img.get('id', '') in enhanced_context}
+                _img_ids_all = {img.get('id', '') for img in selected_images if img.get('id', '')}
+                _missing_ids = _img_ids_all - _img_ids_in_ctx
+                if _missing_ids:
+                    logger.warning(f"[P0] 图片描述未完整注入 context: missing={_missing_ids}, total={len(selected_images)}")
+
             # 对比类查询：添加结构化对比指令
             if intent and intent.intent == "comparison" and intent.sub_queries:
                 comparison_instruction = (