Collect Jimmy Kimmel Live and Hollywood block references; skip AVIF frames in the contact sheet

tools/refcollect.py

@@ -339,12 +339,18 @@ def cmd_sheet(args) -> int:
     images = []
     for row in rows:
         path = out_dir / row["file"]
-        if path.is_file():
+        if not path.is_file():
+            continue
+        try:
             with Image.open(path) as img:
                 img.load()
             images.append(img.convert("RGB"))
+        except Exception as exc:  # noqa: BLE001 - AVIF/misnamed or corrupt frames
+            print(f"  skip unreadable {path.name}: {exc.__class__.__name__}",
+                  file=sys.stderr)
     if not images:
-        sys.exit("error: no downloaded frames in this folder")
+        sys.exit("error: no readable frames in this folder (convert AVIF/webp "
+                 "files with ffmpeg first)")
     cell = 320
     cols = 4
     rows_count = (len(images) + cols - 1) // cols