feat: enhance image URL handling in base_image_generate_node.py to support data URLs

Author: wxg0103

apps/application/flow/step_node/image_generate_step_node/impl/base_image_generate_node.py

@@ -42,8 +42,18 @@ def execute(self, model_id, prompt, negative_prompt, dialogue_number, dialogue_t
         file_urls = []
         for image_url in image_urls:
             file_name = 'generated_image.png'
-            if isinstance(image_url, str) and image_url.startswith('http'):
-                image_url = requests.get(image_url).content
+            if isinstance(image_url, str):
+                if image_url.startswith('http'):
+                    # HTTP URL 情况
+                    image_url = requests.get(image_url).content
+                elif image_url.startswith('data:image'):
+                    # Data URL 格式 (data:image/png;base64,...)
+                    import base64
+                    header, encoded = image_url.split(',', 1)
+                    image_url = base64.b64decode(encoded)
+                else:
+                    import base64
+                    image_url = base64.b64decode(image_url)
             file = bytes_to_uploaded_file(image_url, file_name)
             file_url = self.upload_file(file)
             file_urls.append(file_url)