diff --git a/sdk/python/ragflow_sdk/modules/chunk.py b/sdk/python/ragflow_sdk/modules/chunk.py
index 49092931d8..f70d152691 100644
--- a/sdk/python/ragflow_sdk/modules/chunk.py
+++ b/sdk/python/ragflow_sdk/modules/chunk.py
@@ -29,6 +29,7 @@ class Chunk(Base):
     def __init__(self, rag, res_dict):
         self.id = ""
         self.content = ""
+        self.image_id = ""
         self.important_keywords = []
         self.tag_kwd = []
         self.questions = []
diff --git a/test/unit_test/sdk/test_chunk_image_id.py b/test/unit_test/sdk/test_chunk_image_id.py
new file mode 100644
index 0000000000..0e35ab10d8
--- /dev/null
+++ b/test/unit_test/sdk/test_chunk_image_id.py
@@ -0,0 +1,107 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+"""Keep image references when constructing chunks from public SDK endpoints."""
+
+import json
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from threading import Thread
+from urllib.parse import urlsplit
+
+import pytest
+from ragflow_sdk import Chunk, Document, RAGFlow
+
+pytestmark = pytest.mark.p2
+
+
+@pytest.fixture
+def chunk_api():
+    """Return the chunk envelopes used by add, list and retrieval endpoints."""
+    state = {"chunk": {"id": "chunk-1", "content": "caption", "document_id": "doc", "dataset_id": "kb"}, "requests": []}
+
+    class Handler(BaseHTTPRequestHandler):
+        def log_message(self, *args):
+            """Keep local HTTP request logging out of the test output."""
+
+        def respond(self):
+            """Serve only the expected SDK method and endpoint combinations."""
+            path = urlsplit(self.path).path
+            state["requests"].append((self.command, path))
+            self.rfile.read(int(self.headers.get("Content-Length", "0")))
+            if (self.command, path) == ("POST", "/api/v1/datasets/kb/documents/doc/chunks"):
+                data = {"chunk": state["chunk"]}
+            elif (self.command, path) in {
+                ("GET", "/api/v1/datasets/kb/documents/doc/chunks"),
+                ("POST", "/api/v1/retrieval"),
+            }:
+                data = {"chunks": [state["chunk"]], "total": 1}
+            else:
+                self.send_error(404, "Unexpected SDK endpoint")
+                return
+            body = json.dumps({"code": 0, "data": data}).encode()
+            self.send_response(200)
+            self.send_header("Content-Type", "application/json")
+            self.send_header("Content-Length", str(len(body)))
+            self.end_headers()
+            self.wfile.write(body)
+
+        do_GET = respond
+        do_POST = respond
+
+    server = ThreadingHTTPServer(("127.0.0.1", 0), Handler)
+    thread = Thread(target=server.serve_forever, daemon=True)
+    thread.start()
+    try:
+        yield RAGFlow("test-key", f"http://127.0.0.1:{server.server_port}"), state
+    finally:
+        server.shutdown()
+        server.server_close()
+        thread.join()
+
+
+@pytest.mark.parametrize("endpoint", ["add", "list", "retrieve"])
+@pytest.mark.parametrize("image_id", ["kb-image-1", ""])
+def test_chunk_endpoints_preserve_image_id(chunk_api, endpoint, image_id):
+    """Preserve image IDs through the correct add, list and retrieval routes."""
+    rag, state = chunk_api
+    state["chunk"]["image_id"] = image_id
+    doc = Document(rag, {"id": "doc", "dataset_id": "kb"})
+    if endpoint == "add":
+        chunk = doc.add_chunk("caption")
+    elif endpoint == "list":
+        chunk = doc.list_chunks()[0]
+    else:
+        chunk = rag.retrieve(["kb"], question="caption")[0]
+    assert chunk.image_id == image_id
+    assert chunk.to_json()["image_id"] == image_id
+    assert chunk.content == "caption"
+    expected_request = {
+        "add": ("POST", "/api/v1/datasets/kb/documents/doc/chunks"),
+        "list": ("GET", "/api/v1/datasets/kb/documents/doc/chunks"),
+        "retrieve": ("POST", "/api/v1/retrieval"),
+    }[endpoint]
+    assert state["requests"] == [expected_request]
+
+
+def test_chunk_without_an_image_field_defaults_to_empty_string():
+    """Use the documented empty default when the response omits image_id."""
+    assert Chunk(None, {"id": "text-chunk"}).image_id == ""
+
+
+def test_unknown_chunk_fields_are_still_filtered():
+    """Keep unrelated response fields out of the public serialized chunk."""
+    chunk = Chunk(None, {"id": "chunk", "internal_field": "not public"})
+    assert "internal_field" not in chunk.to_json()