Fix: image not displaying thumbnails when using pipeline (#12574)

### What problem does this PR solve?

Fix image not displaying thumbnails when using pipeline.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

rag/svr/task_executor.py

@@ -300,6 +300,11 @@ async def build_chunks(task, progress_callback):
                 (chunk["content_with_weight"] + str(d["doc_id"])).encode("utf-8", "surrogatepass")).hexdigest()
             d["create_time"] = str(datetime.now()).replace("T", " ")[:19]
             d["create_timestamp_flt"] = datetime.now().timestamp()
+
+            if d.get("img_id"):
+                docs.append(d)
+                return
+
             if not d.get("image"):
                 _ = d.pop("image", None)
                 d["img_id"] = ""