diff --git a/generate_thumbnails.py b/generate_thumbnails.py
index 27e01bc..ecd9632 100644
--- a/generate_thumbnails.py
+++ b/generate_thumbnails.py
@@ -1,13 +1,84 @@
 import logging
+import os
 import pprint
 
 from pelican import signals
+from PIL import Image
 
 log = logging.getLogger(__name__)
 
-def generator_finalized(context):
-    for article in context['articles']:
-        pass
+THUMBNAIL_MAX_SIZE = 448
+
+def generator_finalized(generator):
+    """
+    Generates thumbnails for images specified in article metadata.
+    """
+    output_path = generator.settings['OUTPUT_PATH']
+    content_path = generator.settings['PATH']
+    thumb_dir = os.path.join(output_path, 'media', 'thumbs')
+
+    if not os.path.exists(thumb_dir):
+        try:
+            os.makedirs(thumb_dir)
+            log.info(f"Created thumbnail directory: {thumb_dir}")
+        except OSError as e:
+            log.error(f"Could not create thumbnail directory {thumb_dir}: {e}")
+            return
+
+    for article in generator.articles:
+        if hasattr(article, 'image'):
+            image_path_rel_to_content = article.image
+            # image_path_rel_to_content is often like 'media/imagename.jpg'
+            # or just 'imagename.jpg' if it's directly in 'content/media/'
+            # and STATIC_PATHS includes 'media'.
+            # We assume article.image is a path relative to the 'content' folder.
+            
+            source_image_full_path = os.path.join(content_path, image_path_rel_to_content)
+
+            if not os.path.exists(source_image_full_path):
+                log.warning(f"Source image not found for article '{article.slug}': {source_image_full_path}")
+                continue
+
+            image_filename = os.path.basename(image_path_rel_to_content)
+            thumb_path = os.path.join(thumb_dir, image_filename)
+
+            try:
+                log.debug(f"Processing image: {source_image_full_path}")
+                img = Image.open(source_image_full_path)
+                
+                # Preserve original format, handle potential conversion issues for some modes
+                original_format = img.format
+                if img.mode == 'P' and 'transparency' in img.info: # Palette mode with transparency
+                    img = img.convert('RGBA')
+                elif img.mode not in ('RGB', 'RGBA', 'L'): # L is grayscale
+                    log.info(f"Converting image {image_filename} from mode {img.mode} to RGB for thumbnailing.")
+                    img = img.convert('RGB')
+
+                img.thumbnail((THUMBNAIL_MAX_SIZE, THUMBNAIL_MAX_SIZE))
+                
+                save_kwargs = {}
+                if original_format:
+                    save_kwargs['format'] = original_format
+                if original_format == 'JPEG':
+                    save_kwargs['quality'] = 85 # Adjust quality for JPEGs
+                    save_kwargs['optimize'] = True
+                elif original_format == 'PNG':
+                    save_kwargs['optimize'] = True
+
+                img.save(thumb_path, **save_kwargs)
+                log.info(f"Generated thumbnail for '{article.slug}': {thumb_path}")
+                
+                # Optionally, add thumbnail URL to article metadata if needed by templates
+                # This depends on how SITEURL and paths are structured.
+                # For now, just creating the file.
+                # article.thumbnail_url = f"{generator.settings.get('SITEURL', '')}/media/thumbs/{image_filename}"
+
+            except FileNotFoundError:
+                log.error(f"Image file not found: {source_image_full_path}")
+            except IOError as e:
+                log.error(f"Could not open or process image {source_image_full_path}: {e}")
+            except Exception as e:
+                log.error(f"An unexpected error occurred while processing {source_image_full_path}: {e}")
 
 
 def register():