diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 000000000..27d7f13b0
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1,2 @@
+* @analysiscenter/codeowners
+
diff --git a/.github/workflows/test-install.yml b/.github/workflows/test-install.yml
index f8279c352..b14bd73ed 100644
--- a/.github/workflows/test-install.yml
+++ b/.github/workflows/test-install.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.9, '3.10', 3.11, 3.12]
+        python-version: [3.9, '3.10', 3.11, 3.12, 3.13]
 
     runs-on: ${{ matrix.os }}
 
@@ -52,7 +52,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.9, '3.10', 3.11, 3.12]
+        python-version: [3.9, '3.10', 3.11, 3.12, 3.13]
 
     runs-on: ${{ matrix.os }}
 
@@ -87,7 +87,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.9, '3.10', 3.11, 3.12]
+        python-version: [3.9, '3.10', 3.11, 3.12, 3.13]
 
     runs-on: ${{ matrix.os }}
 
@@ -151,7 +151,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.9, '3.10', 3.11, 3.12]
+        python-version: [3.9, '3.10', 3.11, 3.12, 3.13]
 
     runs-on: ${{ matrix.os }}
 
diff --git a/batchflow/__init__.py b/batchflow/__init__.py
index 5f2b6b6b4..918200f34 100644
--- a/batchflow/__init__.py
+++ b/batchflow/__init__.py
@@ -23,7 +23,6 @@
 from .sampler import Sampler, ConstantSampler, NumpySampler, HistoSampler, ScipySampler
 from .utils import save_data_to, read_data_from
 from .utils_random import make_rng, make_seed_sequence, spawn_seed_sequence
-from .utils_telegram import TelegramMessage
 from .utils_transforms import Normalizer, Quantizer
 
 
@@ -34,7 +33,7 @@
 pylint_notebook = make_delayed_import(module='.utils_notebook', package=__name__, attribute='pylint_notebook')
 get_available_gpus = make_delayed_import(module='.utils_notebook', package=__name__, attribute='get_available_gpus')
 set_gpus = make_delayed_import(module='.utils_notebook', package=__name__, attribute='set_gpus')
-
+TelegramMessage = make_delayed_import(module='.utils_telegram', package=__name__, attribute='TelegramMessage')
 
 try:
     __version__ = version('batchflow')
diff --git a/batchflow/notifier.py b/batchflow/notifier.py
index 5049d473f..e7440a587 100755
--- a/batchflow/notifier.py
+++ b/batchflow/notifier.py
@@ -19,7 +19,6 @@
 
 from .named_expr import NamedExpression, eval_expr
 from .monitor import ResourceMonitor, MONITOR_ALIASES
-from .utils_telegram import TelegramMessage
 
 
 
@@ -255,6 +254,8 @@ def __init__(self, bar='a', disable=False, frequency=1, monitors=None, graphs=No
         # Prepare Telegram notifications
         self.telegram = telegram
         if self.telegram or initialize_telegram:
+            from .utils_telegram import TelegramMessage
+
             self.telegram_text = TelegramMessage(token=token, chat_id=chat_id, silent=silent)
             self.telegram_media = TelegramMessage(token=token, chat_id=chat_id, silent=silent)
 
diff --git a/batchflow/utils_telegram.py b/batchflow/utils_telegram.py
index b5a59d2b5..59e552ab2 100644
--- a/batchflow/utils_telegram.py
+++ b/batchflow/utils_telegram.py
@@ -1,7 +1,6 @@
 """ A class to send updateable content messages to Telegram. """
 import os
 import json
-import imghdr
 from uuid import uuid4
 from io import BytesIO
 from concurrent.futures import ThreadPoolExecutor
@@ -148,6 +147,8 @@ def delete(self):
     def content_to_dict(content, group=True, **kwargs):
         """ Convert a content (either a path to photo or matplotlib figure) to a telegram-acceptable dictionary. """
         # Convert content to a bytestring
+        from PIL import Image
+
         if isinstance(content, str):
             bytes_ = TelegramMessage.path_to_bytes(content)
         else:
@@ -155,7 +156,8 @@ def content_to_dict(content, group=True, **kwargs):
 
         # Create unique id of attachment, pack entities in json
         attach_id = f'attached{uuid4().hex}'
-        attach_fmt = imghdr.what(None, bytes_)
+        image = Image.open(BytesIO(bytes_))
+        attach_fmt = image.format.lower()
 
         media_dict = {'media': f'attach://{attach_id}', 'type': 'photo'}
         media_dict = [media_dict] if group else media_dict
diff --git a/pyproject.toml b/pyproject.toml
index b0db10178..31c0a9d41 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -70,6 +70,10 @@ jupyter = [
     "requests"
 ]
 
+telegram = [
+    "pillow>=9.4,<11.0",
+]
+
 other = [
     "urllib3>=1.25"
 ]
diff --git a/uv.lock b/uv.lock
index b7a8c069f..4249d0abc 100644
--- a/uv.lock
+++ b/uv.lock
@@ -182,6 +182,9 @@ research = [
     { name = "multiprocess" },
     { name = "py-nbtools" },
 ]
+telegram = [
+    { name = "pillow" },
+]
 
 [package.metadata]
 requires-dist = [
@@ -201,6 +204,7 @@ requires-dist = [
     { name = "numpy", specifier = ">=1.26" },
     { name = "pandas", marker = "extra == 'dev'", specifier = ">=0.24" },
     { name = "pillow", marker = "extra == 'image'", specifier = ">=9.4,<11.0" },
+    { name = "pillow", marker = "extra == 'telegram'", specifier = ">=9.4,<11.0" },
     { name = "psutil", marker = "extra == 'monitor'" },
     { name = "ptflops", marker = "extra == 'nn'", specifier = ">=0.6" },
     { name = "py-nbtools", marker = "extra == 'research'", specifier = ">=0.9.14" },