diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index a07bd9f6d0..be5ad7ae1c 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -976,6 +976,25 @@ async def apply_source_context_to_messages(
         )
 
 
+BASE64_IMAGE_DATA_URI_RE = re.compile(r'data:image/[a-zA-Z0-9.+-]+;base64,[A-Za-z0-9+/]+={0,2}', re.IGNORECASE)
+
+
+def extract_base64_images(value: Any, files: list) -> Any:
+    """Move base64 image data URIs out of a tool result so they do not reach the model as text."""
+    if isinstance(value, str):
+        if BASE64_IMAGE_DATA_URI_RE.fullmatch(value):
+            files.append({'type': 'image', 'url': value})
+            return '[image]'
+        return value
+    if isinstance(value, dict):
+        return {key: extract_base64_images(item, files) for key, item in value.items()}
+    if isinstance(value, list):
+        return [extract_base64_images(item, files) for item in value]
+    if isinstance(value, tuple):
+        return tuple(extract_base64_images(item, files) for item in value)
+    return value
+
+
 async def process_tool_result(
     request,
     tool_function_name,
@@ -1161,8 +1180,9 @@ async def process_tool_result(
                             tool_response.append(resource.get('uri'))
             tool_result = tool_response[0] if len(tool_response) == 1 else tool_response
         else:  # OpenAPI
-            for item in tool_result:
-                if isinstance(item, str) and item.startswith('data:'):
+            # Images are left to extract_base64_images below, which attaches them so the model can see them.
+            for item in list(tool_result):
+                if isinstance(item, str) and item.startswith('data:') and not BASE64_IMAGE_DATA_URI_RE.fullmatch(item):
                     tool_result_files.append(
                         {
                             'type': 'data',
@@ -1171,6 +1191,8 @@ async def process_tool_result(
                     )
                     tool_result.remove(item)
 
+    tool_result = extract_base64_images(tool_result, tool_result_files)
+
     if isinstance(tool_result, list):
         tool_result = {'results': tool_result}