diff --git a/tests/e2e/accuracy/wan22_i2v/test_wan22_i2v_video_similarity.py b/tests/e2e/accuracy/wan22_i2v/test_wan22_i2v_video_similarity.py
index 17e4fc0f2..5300f1c6e 100644
--- a/tests/e2e/accuracy/wan22_i2v/test_wan22_i2v_video_similarity.py
+++ b/tests/e2e/accuracy/wan22_i2v/test_wan22_i2v_video_similarity.py
@@ -359,9 +359,18 @@ def _validate_image_source(source: str) -> None:
 
 
 def _build_online_image_reference(source: str) -> str:
-    if _is_remote_image_source(source) or source.startswith("data:image"):
+    if source.startswith("data:image"):
         return source
 
+    if _is_remote_image_source(source):
+        response = requests.get(source, timeout=60)
+        response.raise_for_status()
+        mime_type = response.headers.get("Content-Type", "").split(";", 1)[0].strip()
+        if not mime_type.startswith("image/"):
+            mime_type = guess_type(urlparse(source).path)[0] or "image/png"
+        encoded = b64encode(response.content).decode("ascii")
+        return f"data:{mime_type};base64,{encoded}"
+
     image_path = Path(source)
     mime_type = guess_type(image_path.name)[0] or "image/png"
     encoded = b64encode(image_path.read_bytes()).decode("ascii")
@@ -479,7 +488,10 @@ def _send_video_request_with_timeout(
         headers={"Accept": "application/json"},
         timeout=60,
     )
-    response.raise_for_status()
+    try:
+        response.raise_for_status()
+    except requests.HTTPError as exc:
+        raise requests.HTTPError(f"{exc}; response body: {response.text}", response=response) from exc
     job_data = response.json()
     video_id = job_data["id"]
     openai_client._wait_until_video_completed(video_id, timeout_seconds=timeout_seconds)