diff --git a/openpype/hosts/webpublisher/plugins/publish/collect_published_files.py b/openpype/hosts/webpublisher/plugins/publish/collect_published_files.py
index 2bf097de418..79ed499a20b 100644
--- a/openpype/hosts/webpublisher/plugins/publish/collect_published_files.py
+++ b/openpype/hosts/webpublisher/plugins/publish/collect_published_files.py
@@ -86,6 +86,7 @@ def process(self, context):
             first_file = task_data["files"][0]
 
             _, extension = os.path.splitext(first_file)
+            extension = extension.lower()
             family, families, tags = self._get_family(
                 self.task_type_to_family,
                 task_type,
@@ -180,6 +181,7 @@ def _get_subset_name(self, family, subset_template, task_name, variant):
 
     def _get_single_repre(self, task_dir, files, tags):
         _, ext = os.path.splitext(files[0])
+        ext = ext.lower()
         repre_data = {
             "name": ext[1:],
             "ext": ext[1:],
@@ -199,6 +201,7 @@ def _process_sequence(self, files, task_dir, tags):
         frame_start = list(collections[0].indexes)[0]
         frame_end = list(collections[0].indexes)[-1]
         ext = collections[0].tail
+        ext = ext.lower()
         repre_data = {
             "frameStart": frame_start,
             "frameEnd": frame_end,
@@ -244,8 +247,17 @@ def _get_family(self, settings, task_type, is_sequence, extension):
         for config in families_config:
             if is_sequence != config["is_sequence"]:
                 continue
-            if (extension in config["extensions"] or
-                    '' in config["extensions"]):  # all extensions setting
+            extensions = config.get("extensions") or []
+            lower_extensions = set()
+            for ext in extensions:
+                if ext:
+                    ext = ext.lower()
+                    if ext.startswith("."):
+                        ext = ext[1:]
+                    lower_extensions.add(ext)
+
+            # all extensions setting
+            if not lower_extensions or extension in lower_extensions:
                 found_family = config["result_family"]
                 break
 
diff --git a/openpype/plugins/publish/extract_review.py b/openpype/plugins/publish/extract_review.py
index 1f9b30fba36..f299d1c6e92 100644
--- a/openpype/plugins/publish/extract_review.py
+++ b/openpype/plugins/publish/extract_review.py
@@ -179,7 +179,7 @@ def _single_frame_filter(self, input_filepaths, output_defs):
         single_frame_image = False
         if len(input_filepaths) == 1:
             ext = os.path.splitext(input_filepaths[0])[-1]
-            single_frame_image = ext in IMAGE_EXTENSIONS
+            single_frame_image = ext.lower() in IMAGE_EXTENSIONS
 
         filtered_defs = []
         for output_def in output_defs:
@@ -501,7 +501,7 @@ def prepare_temp_data(self, instance, repre, output_def):
                 first_sequence_frame += handle_start
 
             ext = os.path.splitext(repre["files"][0])[1].replace(".", "")
-            if ext in self.alpha_exts:
+            if ext.lower() in self.alpha_exts:
                 input_allow_bg = True
 
         return {
@@ -934,6 +934,8 @@ def input_output_paths(self, new_repre, output_def, temp_data):
         if output_ext.startswith("."):
             output_ext = output_ext[1:]
 
+        output_ext = output_ext.lower()
+
         # Store extension to representation
         new_repre["ext"] = output_ext