diff --git a/app/api/documents.py b/app/api/documents.py
index f390738..ca01a8b 100644
--- a/app/api/documents.py
+++ b/app/api/documents.py
@@ -1048,6 +1048,19 @@ async def get_document_image_raw(
             DocumentImage.image_key == image_key,
         )
     )
+    if img is None:
+        # clause-KB: 절-문서는 부모 표준 이미지를 공유(md_content=부모 슬라이스) → parent_id 폴백.
+        from sqlalchemy import text as sql_text
+        _par = (await session.execute(
+            sql_text("SELECT parent_id FROM documents WHERE id = :id").bindparams(id=doc_id)
+        )).scalar()
+        if _par is not None:
+            img = await session.scalar(
+                select(DocumentImage).where(
+                    DocumentImage.document_id == _par,
+                    DocumentImage.image_key == image_key,
+                )
+            )
     if img is None:
         raise HTTPException(status_code=404, detail="이미지를 찾을 수 없습니다")