Allow signaling issues in label verification

copienator/commands/grouping.py

@@ -117,7 +117,7 @@ def group_files(file_list):
     return [g['items'] for g in groups]
 
 def stitch_pdf_pages(images_list):
-    """Vertically concatenates a list of PIL images with no separator."""
+    """Stack PIL images vertically, centering each within the widest image."""
     if not images_list:
         return None
     if len(images_list) == 1:
@@ -130,7 +130,7 @@ def stitch_pdf_pages(images_list):
 
     y_offset = 0
     for img in images_list:
-        combined.paste(img, (0, y_offset))
+        combined.paste(img, ((max_width - img.width) // 2, y_offset))
         y_offset += img.height
 
     return combined