diff --git a/generate_thumbnails.py b/generate_thumbnails.py
index f6241a1..1a4d6ba 100644
--- a/generate_thumbnails.py
+++ b/generate_thumbnails.py
@@ -43,6 +43,12 @@ def generator_finalized(generator):
             image_filename = os.path.basename(image_path_rel_to_content)
             thumb_path = os.path.join(thumb_dir, image_filename)
 
+            _, ext = os.path.splitext(image_filename)
+            ext_lower = ext.lower()
+            if ext_lower not in ['.jpg', '.jpeg', '.png']:
+                log.info(f"Skipping non-JPG/PNG image for article '{article.slug}': {image_filename}")
+                continue
+
             try:
                 log.debug(f"Processing image: {source_image_full_path}")
                 img = Image.open(source_image_full_path)