diff --git a/scripts/contact_sheet_registry.py b/scripts/contact_sheet_registry.py
new file mode 100644
index 0000000..18343d9
--- /dev/null
+++ b/scripts/contact_sheet_registry.py
@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+"""Tweet contact-sheet registry for the 201+ hand-drawn style gallery.
+
+G-category sheets are 4x4 (CAPACITY=16) contact sheets named
+``G_{start:03}-{end:03}.png`` under ``images/``; the final sheet may be
+incomplete. The active-sheet bookkeeping lives in
+``handdraw-style-prompter/references/contact_sheet_state.json``.
+
+This module was previously missing from the published repository. The
+implementation is reconstructed from the contracts enforced by
+``handdraw-style-prompter/scripts/validate_library.py``.
+"""
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+IMAGES = ROOT / "images"
+STATE_FILE = ROOT / "handdraw-style-prompter" / "references" / "contact_sheet_state.json"
+
+# 4x4 tile grid per contact sheet.
+CAPACITY = 16
+
+SHEET = re.compile(r"^G_(\d{3})(?:-(\d{3}))?\.png$")
+
+
+def parse_sheet(path: Path) -> tuple[int, int] | None:
+    """Return (start, end) style numbers encoded in a G-sheet filename.
+
+    A bare ``G_201.png`` counts as a single-style sheet (start == end).
+    Non-matching names return ``None`` so callers can skip them.
+    """
+    match = SHEET.match(Path(path).name)
+    if not match:
+        return None
+    start = int(match.group(1))
+    end = int(match.group(2)) if match.group(2) else start
+    if end < start:
+        return None
+    return start, end
+
+
+def sheet_path(start: int, end: int) -> Path:
+    """Canonical path for the sheet covering styles ``start``–``end``."""
+    if start == end:
+        return IMAGES / f"G_{start:03}.png"
+    return IMAGES / f"G_{start:03}-{end:03}.png"
diff --git a/scripts/style_asset_paths.py b/scripts/style_asset_paths.py
new file mode 100644
index 0000000..8732300
--- /dev/null
+++ b/scripts/style_asset_paths.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""Numbered style asset path helpers (single source of truth for layout).
+
+Assets live in 200-number buckets under ``images/individual/``:
+
+- ``001-200/001.png`` … ``401-600/xxx.png``  — per-style single images
+- ``001-200/048_grid.jpg``                   — optional four-panel grid,
+  same bucket as the matching single image; takes priority as a
+  generation reference when present.
+
+This module was previously missing from the published repository. The
+implementation is reconstructed from the contracts enforced by
+``handdraw-style-prompter/scripts/validate_library.py``.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+INDIVIDUAL = ROOT / "images" / "individual"
+BUCKET_SIZE = 200
+
+
+def _number(value: int | str) -> int:
+    try:
+        number = int(value)
+    except (TypeError, ValueError):
+        raise ValueError(f"Style number must be an integer, got {value!r}")
+    if number < 1:
+        raise ValueError(f"Style number must be >= 1, got {number}")
+    return number
+
+
+def bucket_name(value: int | str) -> str:
+    """Return the 200-style bucket directory name, e.g. 1 -> '001-200'."""
+    number = _number(value)
+    start = (number - 1) // BUCKET_SIZE * BUCKET_SIZE + 1
+    return f"{start:03}-{start + BUCKET_SIZE - 1:03}"
+
+
+def bucket_dir(value: int | str) -> Path:
+    return INDIVIDUAL / bucket_name(value)
+
+
+def single_path(value: int | str) -> Path:
+    """Path to the numbered single image, e.g. 48 -> .../001-200/048.png."""
+    number = _number(value)
+    return bucket_dir(number) / f"{number:03}.png"
+
+
+def grid_path(value: int | str) -> Path:
+    """Path to the four-panel grid image, e.g. 217 -> .../201-400/217_grid.jpg."""
+    number = _number(value)
+    return bucket_dir(number) / f"{number:03}_grid.jpg"