diff --git a/camel/model_backend.py b/camel/model_backend.py
index 2c664ba33..de974d290 100644
--- a/camel/model_backend.py
+++ b/camel/model_backend.py
@@ -92,11 +92,11 @@ def run(self, *args, **kwargs):
                 "gpt-4-32k": 32768,
                 "gpt-4-turbo": 100000,
             }
-            num_max_token = num_max_token_map[self.model_type.value]
+            num_max_token = num_max_token_map.get(self.model_type.value, os.environ['CHATDEV_NUM_MAX_TOKEN'])
             num_max_completion_tokens = num_max_token - num_prompt_tokens
             self.model_config_dict['max_tokens'] = num_max_completion_tokens
 
-            response = client.chat.completions.create(*args, **kwargs, model=self.model_type.value,
+            response = client.chat.completions.create(*args, **kwargs, model=os.environ.get('CHATDEV_CUSTOM_MODEL', self.model_type.value),
                                                       **self.model_config_dict)
 
             cost = prompt_cost(
diff --git a/chatdev/chat_env.py b/chatdev/chat_env.py
index b9504969d..c85271bac 100644
--- a/chatdev/chat_env.py
+++ b/chatdev/chat_env.py
@@ -1,5 +1,6 @@
 import os
 import re
+import base64
 import shutil
 import signal
 import subprocess
@@ -12,7 +13,10 @@
 from chatdev.codes import Codes
 from chatdev.documents import Documents
 from chatdev.roster import Roster
-from chatdev.utils import log_visualize
+from chatdev.utils import (
+	log_visualize,
+	is_url
+)
 from ecl.memory import Memory
 
 try:
@@ -214,12 +218,15 @@ def write_meta(self) -> None:
 
     def generate_images_from_codes(self):
         def download(img_url, file_name):
-            r = requests.get(img_url)
+            if is_url(img_url):
+                content = requests.get(img_url).content
+            else:
+                content = base64.b64decode(img_url)
             filepath = os.path.join(self.env_dict['directory'], file_name)
             if os.path.exists(filepath):
                 os.remove(filepath)
             with open(filepath, "wb") as f:
-                f.write(r.content)
+                f.write(content)
                 print("{} Downloaded".format(filepath))
 
         regex = r"(\w+.png)"
@@ -241,28 +248,39 @@ def download(img_url, file_name):
                 print("{}: {}".format(filename, desc))
                 if openai_new_api:
                     response = openai.images.generate(
+                        model=os.environ.get('CHATDEV_CUSTOM_IMAGE_MODEL', None),
                         prompt=desc,
                         n=1,
                         size="256x256"
                     )
-                    image_url = response.data[0].url
+                    try:
+                        image_url = response.data[0].url
+                    except KeyError:
+                        image_url = response.data['url']
                 else:
                     response = openai.Image.create(
+                        model=os.environ.get('CHATDEV_CUSTOM_IMAGE_MODEL', None),
                         prompt=desc,
                         n=1,
                         size="256x256"
                     )
-                    image_url = response['data'][0]['url']
+                    try:
+                        image_url = response['data'][0]['url']
+                    except KeyError:
+                        image_url = response['data']['url']
                 download(image_url, filename)
 
     def get_proposed_images_from_message(self, messages):
         def download(img_url, file_name):
-            r = requests.get(img_url)
+            if is_url(img_url):
+                content = requests.get(img_url).content
+            else:
+                content = base64.b64decode(img_url)
             filepath = os.path.join(self.env_dict['directory'], file_name)
             if os.path.exists(filepath):
                 os.remove(filepath)
             with open(filepath, "wb") as f:
-                f.write(r.content)
+                f.write(content)
                 print("{} Downloaded".format(filepath))
 
         regex = r"(\w+.png):(.*?)\n"
@@ -292,6 +310,7 @@ def download(img_url, file_name):
 
                 if openai_new_api:
                     response = openai.images.generate(
+                        model=os.environ.get('CHATDEV_CUSTOM_IMAGE_MODEL', None),
                         prompt=desc,
                         n=1,
                         size="256x256"
@@ -299,6 +318,7 @@ def download(img_url, file_name):
                     image_url = response.data[0].url
                 else:
                     response = openai.Image.create(
+                        model=os.environ.get('CHATDEV_CUSTOM_IMAGE_MODEL', None),
                         prompt=desc,
                         n=1,
                         size="256x256"
diff --git a/chatdev/utils.py b/chatdev/utils.py
index 4f17947ca..47d40f487 100644
--- a/chatdev/utils.py
+++ b/chatdev/utils.py
@@ -3,8 +3,11 @@
 import re
 import time
 
+from urllib.parse import urlparse
+
 import markdown
 import inspect
+
 from camel.messages.system_messages import SystemMessage
 from visualizer.app import send_msg
 
@@ -87,3 +90,13 @@ def escape_string(value):
     value = re.sub(r'<[^>]*>', '', value)
     value = value.replace("\n", " ")
     return value
+
+def is_url(url):
+    """
+    Adapted from https://stackoverflow.com/questions/7160737/how-to-validate-a-url-in-python-malformed-or-not
+    """
+    try:
+       result = urlparse(url)
+       return all([result.scheme, result.netloc])
+    except ValueError:
+       return False