diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2189cb23a5ad..b1d298de559f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed multiple tasks moving (<https://github.com/openvinotoolkit/cvat/pull/3517>)
 - Fixed task creating CLI parameter (<https://github.com/openvinotoolkit/cvat/pull/3519>)
 - Fixed import for MOTS format (<https://github.com/openvinotoolkit/cvat/pull/3612>)
+- Fixed extension comparison in task frames CLI (<https://github.com/openvinotoolkit/cvat/pull/3674>)
 
 ## \[1.5.0] - 2021-08-02
 
diff --git a/utils/cli/core/core.py b/utils/cli/core/core.py
index 839dd9b341a4..2c05d4bcc276 100644
--- a/utils/cli/core/core.py
+++ b/utils/cli/core/core.py
@@ -170,7 +170,7 @@ def tasks_frame(self, task_id, frame_ids, outdir='', quality='original', **kwarg
             # FIXME It is better to use meta information from the server
             # to determine the extension
             # replace '.jpe' or '.jpeg' with a more used '.jpg'
-            if im_ext == '.jpe' or '.jpeg' or None:
+            if im_ext in ('.jpe', '.jpeg', None):
                 im_ext = '.jpg'
 
             outfile = 'task_{}_frame_{:06d}{}'.format(task_id, frame_id, im_ext)