diff --git a/package_linter.py b/package_linter.py
index 9da6b08..6f07c87 100755
--- a/package_linter.py
+++ b/package_linter.py
@@ -590,20 +590,24 @@ class App(TestSuite):
 """
                 )
 
-        if os.path.exists(app.path + "/doc/screenshots"):
+        if os.path.exists(os.path.join(app.path, "doc/screenshots")):
             du_output = subprocess.check_output(["du", "-sb", app.path + "/doc/screenshots"], shell=False)
             screenshots_size = int(du_output.split()[0])
             if screenshots_size > 512000:
                 yield Info("Consider keeping the content of doc/screenshots under ~512Kb for better UI/UX once the screenshots will be integrated in the webadmin app's catalog (to be discussed with the team)")
 
-            for path in os.listdir(app.path + "/doc/screenshots"):
-                if path == ".gitkeep":
-                    continue
-                if os.path.isdir(path):
-                    continue
-                if all(not path.lower().endswith(ext) for ext in [".jpg", ".jpeg", ".png", ".gif", ".webp"]):
-                    yield Warning("In the doc/screenshots folder, only .jpg, .jpeg, .png, .webp and .gif are accepted")
-                    break
+            for _, _, files in os.walk(os.path.join(app.path, "doc/screenshots")):
+                for file in files:
+                    if file == ".gitkeep":
+                        continue
+                    if all(
+                        not file.lower().endswith(ext)
+                        for ext in [".jpg", ".jpeg", ".png", ".gif", ".webp"]
+                    ):
+                        yield Warning(
+                            "In the doc/screenshots folder, only .jpg, .jpeg, .png, .webp and .gif are accepted"
+                        )
+                        break
 
     @test()
     def doc_dir_v2(app):