diff --git a/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md b/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
index 6085f43..6e948f9 100644
--- a/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
+++ b/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
@@ -1197,7 +1197,6 @@ _**Agent (model default, mode Agent)**_
---
-
Creating a diagnostic script to identify which sequences were skipped and why:
@@ -1337,7 +1336,6 @@ UnicodeEncodeError: 'charmap' codec can't encode character '\u2713' in position
---
-
Fixing the Unicode issue and improving the diagnostic script:
@@ -1476,7 +1474,6 @@ TypeError: expected str, bytes or os.PathLike object, not list
---
-
Fixing the script and listing all folders in the input directory:
@@ -1638,7 +1635,6 @@ HAS PNGs Pack2BagScan_animation 6d (600 PNG files)
---
-
Found 4 folders in the input directory with no PNG files, so they were skipped:
1. **Bag2PackScan_animation 2a** (0 PNG files)
@@ -1666,7 +1662,6 @@ _**Agent (model default, mode Agent)**_
---
-
Updating the script to process JPG files and report when we do:
@@ -1684,7 +1679,6 @@ Updating the script to process JPG files and report when we do:
---
-
Updating the script to skip JPG files and report when we do:
@@ -1789,7 +1783,6 @@ Lines added: 2, lines removed: undefined
---
-
Ensuring `jpg_files` is accessible in the final summary:
@@ -1809,6 +1802,356 @@ Ensuring `jpg_files` is accessible in the final summary:
+---
+
+
+
+ Tool use: **read_lints** • Read lints for 1 file
+
+Lint paths:
+
+- `compress_pngs.py`
+
+Lint results
+
+
+**No lint errors found**
+
+
+
+---
+
+
+
+---
+
+Updated the script to:
+
+1. Scan for both PNG and JPG/JPEG files
+2. Report at the start how many JPG files were found and that they're being ignored
+3. Process only PNG files
+4. Include in the final summary how many JPG files were ignored
+
+When you run it, it will report any JPG files found and skip them, so you'll know which sequences contain JPG files instead of PNGs.
+
+---
+
+_**User (2025-12-11 18:21Z)**_
+
+create a gitignore and ignore the input and output folders pls.
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+
+
+
+---
+
+
+
+Tool use: **write** • Edit file: .gitignore
+
+**Chunk 1**
+Lines added: 3, lines removed: 1
+
+```diff
+@@ -1,1 +1,3 @@
+-
++ input/
++ output/
++
+```
+
+
+
+
+
+---
+
+
+
+---
+
+Created a `.gitignore` file that ignores the `input/` and `output/` folders. Git will ignore these directories and their contents.
+
+---
+
+_**User (2025-12-11 21:39Z)**_
+
+What method does it use to compress the PNGs? are they 16-bit, or 8-bit color? Does it specify?
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+
+Checking the compression method used in the script:
+
+
+---
+
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+
+
+
+---
+
+
+
+---
+
+
+The script uses:
+
+1. Compression method: PIL/Pillow's PNG save with:
+ - `optimize=True` — enables PNG optimization
+ - `compress_level=9` — maximum zlib compression (0-9)
+
+2. Bit depth: Not explicitly set. PIL/Pillow defaults to 8-bit per channel for RGB/RGBA. If the input is 16-bit, it will be converted to 8-bit during the `convert()` call.
+
+3. Color mode: Converts to RGB or RGBA (preserves RGBA for transparency), but doesn't preserve 16-bit data.
+
+If you want to preserve 16-bit depth or use a different compression method, I can update the script. Options:
+- Preserve 16-bit depth if present
+- Use a different compression tool (e.g., pngquant for lossy, optipng/pngcrush for lossless)
+- Add explicit bit depth control
+
+Should I update it?
+
+---
+
+_**User (2025-12-11 21:39Z)**_
+
+Yes, let's preserve 16-bit if present.
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+
+
+Updating the script to preserve 16-bit depth when present:
+
+
+---
+
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+
+
+
+---
+
+
+
+---
+
+
+
+
+
+---
+
+
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 41, lines removed: 8
+
+```diff
+@@ -33,13 +33,46 @@
+ img = Image.open(input_path)
+
+- # Convert to RGB if RGBA and no transparency needed
+- if img.mode == 'RGBA':
+- # Keep RGBA for transparency support
+- img = img.convert('RGBA')
+- elif img.mode != 'RGB':
+- img = img.convert('RGB')
++ # Check if image is 16-bit by examining mode and pixel values
++ is_16bit = False
++ if img.mode == 'I':
++ # 'I' mode (32-bit integer) often represents 16-bit grayscale
++ is_16bit = True
++ elif img.mode in ('RGB', 'RGBA'):
++ # Check if max pixel value exceeds 8-bit range
++ try:
++ # Sample a few pixels to check bit depth
++ sample = img.crop((0, 0, min(100, img.width), min(100, img.height)))
++ max_val = max(sample.getdata())
++ if max_val > 255:
++ is_16bit = True
++ except:
++ pass
++
++ # Preserve 16-bit depth if present, otherwise convert as needed
++ if is_16bit:
++ # Preserve original mode for 16-bit images
++ if img.mode == 'I':
++ # Keep grayscale 16-bit
++ pass
++ elif img.mode == 'RGBA':
++ # Keep RGBA 16-bit
++ pass
++ elif img.mode == 'RGB':
++ # Keep RGB 16-bit
++ pass
++ else:
++ # Convert other 16-bit modes to RGB
++ img = img.convert('RGB')
++ else:
++ # 8-bit images: convert as needed
++ if img.mode == 'RGBA':
++ # Keep RGBA for transparency support
++ img = img.convert('RGBA')
++ elif img.mode != 'RGB':
++ img = img.convert('RGB')
+
+- # Save with maximum compression to output path
+- img.save(str(output_path), 'PNG', optimize=True, compress_level=9)
++ # Save with maximum compression, preserving bit depth
++ save_kwargs = {'optimize': True, 'compress_level': 9}
++ img.save(str(output_path), 'PNG', **save_kwargs)
+ new_size = os.path.getsize(output_path)
+ savings = original_size - new_size
+```
+
+
+
+
+
+---
+
+
+
+---
+
+
+Refining the 16-bit detection to be more accurate:
+
+
+---
+
+
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 29, lines removed: 17
+
+```diff
+@@ -33,35 +33,47 @@
+ img = Image.open(input_path)
+
+- # Check if image is 16-bit by examining mode and pixel values
++ # Check if image is 16-bit
++ # PIL represents 16-bit grayscale as 'I' mode (32-bit integer)
++ # For color images, check pixel values to determine bit depth
+ is_16bit = False
++ original_mode = img.mode
++
+ if img.mode == 'I':
+- # 'I' mode (32-bit integer) often represents 16-bit grayscale
++ # 'I' mode typically represents 16-bit grayscale
+ is_16bit = True
+- elif img.mode in ('RGB', 'RGBA'):
++ elif img.mode in ('RGB', 'RGBA', 'LA'):
+ # Check if max pixel value exceeds 8-bit range
+ try:
+- # Sample a few pixels to check bit depth
+- sample = img.crop((0, 0, min(100, img.width), min(100, img.height)))
+- max_val = max(sample.getdata())
+- if max_val > 255:
+- is_16bit = True
++ # Get a sample of pixels to check
++ pixels = list(img.getdata())
++ if pixels:
++ # Flatten if needed (for multi-channel modes)
++ if isinstance(pixels[0], (tuple, list)):
++ max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
++ else:
++ max_val = max(pixels[:1000])
++ if max_val > 255:
++ is_16bit = True
+ except:
++ # If we can't determine, assume 8-bit to be safe
+ pass
+
+ # Preserve 16-bit depth if present, otherwise convert as needed
+ if is_16bit:
+- # Preserve original mode for 16-bit images
++ # For 16-bit images, preserve the mode
++ # PIL will save 16-bit when mode is 'I' (grayscale) or when using specific modes
+ if img.mode == 'I':
+- # Keep grayscale 16-bit
++ # Keep 16-bit grayscale
+ pass
+- elif img.mode == 'RGBA':
+- # Keep RGBA 16-bit
+- pass
+- elif img.mode == 'RGB':
+- # Keep RGB 16-bit
++ elif img.mode in ('RGB', 'RGBA'):
++ # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
++ # Note: PIL's PNG save may convert 16-bit RGB to 8-bit, but we preserve the mode
+ pass
+ else:
+- # Convert other 16-bit modes to RGB
+- img = img.convert('RGB')
++ # Convert other modes while trying to preserve bit depth
++ if 'A' in img.mode:
++ img = img.convert('RGBA')
++ else:
++ img = img.convert('RGB')
+ else:
+ # 8-bit images: convert as needed
+```
+
+**Chunk 2**
+Lines added: 4, lines removed: 3
+
+```diff
+@@ -72,7 +84,8 @@
+ img = img.convert('RGB')
+
+- # Save with maximum compression, preserving bit depth
+- save_kwargs = {'optimize': True, 'compress_level': 9}
+- img.save(str(output_path), 'PNG', **save_kwargs)
++ # Save with maximum compression
++ # PIL will preserve 16-bit for 'I' mode automatically
++ # For color 16-bit, PIL may convert to 8-bit, but we've preserved the mode
++ img.save(str(output_path), 'PNG', optimize=True, compress_level=9)
+ new_size = os.path.getsize(output_path)
+ savings = original_size - new_size
+```
+
+
+
+
+
+---
+
+
+
+---
+
+
+
---
@@ -1835,62 +2178,23 @@ Lint results
---
-Updated the script to:
+Updated the script to preserve 16-bit depth when present. It:
-1. Scan for both PNG and JPG/JPEG files
-2. Report at the start how many JPG files were found and that they're being ignored
-3. Process only PNG files
-4. Include in the final summary how many JPG files were ignored
+1. **Detects 16-bit images** by:
+ - Checking if the mode is `'I'` (16-bit grayscale)
+ - Sampling pixel values to see if they exceed 255 (indicating 16-bit color)
-When you run it, it will report any JPG files found and skip them, so you'll know which sequences contain JPG files instead of PNGs.
-
----
-
-_**User (2025-12-11 18:21Z)**_
-
-create a gitignore and ignore the input and output folders pls.
-
----
-
-_**Agent (model default, mode Agent)**_
-
-
-
----
-
-
-
-
-
----
-
-
-
-Tool use: **write** • Edit file: .gitignore
-
-**Chunk 1**
-Lines added: 3, lines removed: 1
-
-```diff
-@@ -1,1 +1,3 @@
--
-+ input/
-+ output/
-+
-```
-
-
-
-
-
----
-
-
-
----
-
-
-Created a `.gitignore` file that ignores the `input/` and `output/` folders. Git will ignore these directories and their contents.
+2. **Preserves 16-bit** by:
+ - Keeping the original mode for 16-bit images
+ - Avoiding unnecessary conversions that would reduce bit depth
+
+3. **Handles both**:
+ - **16-bit grayscale** (`'I'` mode): Preserved as 16-bit
+ - **16-bit color** (RGB/RGBA): Mode is preserved; PIL may still save as 8-bit due to library limitations
+
+**Note**: PIL/Pillow fully supports 16-bit grayscale PNGs. For 16-bit color PNGs, PIL may convert to 8-bit when saving, which is a library limitation. If you need true 16-bit color preservation, a different tool (e.g., `pngcrush` or `optipng`) would be needed.
+
+The script now preserves 16-bit depth where possible and avoids unnecessary conversions.
---
diff --git a/compress_pngs.bat b/compress_pngs.bat
index d0d19fb..4c2bd29 100644
--- a/compress_pngs.bat
+++ b/compress_pngs.bat
@@ -2,3 +2,4 @@
python compress_pngs.py
pause
+
diff --git a/compress_pngs.py b/compress_pngs.py
index b39845d..d1f6b97 100644
--- a/compress_pngs.py
+++ b/compress_pngs.py
@@ -32,14 +32,60 @@ def compress_png(input_path, output_path):
original_size = os.path.getsize(input_path)
img = Image.open(input_path)
- # Convert to RGB if RGBA and no transparency needed
- if img.mode == 'RGBA':
- # Keep RGBA for transparency support
- img = img.convert('RGBA')
- elif img.mode != 'RGB':
- img = img.convert('RGB')
+ # Check if image is 16-bit
+ # PIL represents 16-bit grayscale as 'I' mode (32-bit integer)
+ # For color images, check pixel values to determine bit depth
+ is_16bit = False
+ original_mode = img.mode
- # Save with maximum compression to output path
+ if img.mode == 'I':
+ # 'I' mode typically represents 16-bit grayscale
+ is_16bit = True
+ elif img.mode in ('RGB', 'RGBA', 'LA'):
+ # Check if max pixel value exceeds 8-bit range
+ try:
+ # Get a sample of pixels to check
+ pixels = list(img.getdata())
+ if pixels:
+ # Flatten if needed (for multi-channel modes)
+ if isinstance(pixels[0], (tuple, list)):
+ max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
+ else:
+ max_val = max(pixels[:1000])
+ if max_val > 255:
+ is_16bit = True
+ except:
+ # If we can't determine, assume 8-bit to be safe
+ pass
+
+ # Preserve 16-bit depth if present, otherwise convert as needed
+ if is_16bit:
+ # For 16-bit images, preserve the mode
+ # PIL will save 16-bit when mode is 'I' (grayscale) or when using specific modes
+ if img.mode == 'I':
+ # Keep 16-bit grayscale
+ pass
+ elif img.mode in ('RGB', 'RGBA'):
+ # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
+ # Note: PIL's PNG save may convert 16-bit RGB to 8-bit, but we preserve the mode
+ pass
+ else:
+ # Convert other modes while trying to preserve bit depth
+ if 'A' in img.mode:
+ img = img.convert('RGBA')
+ else:
+ img = img.convert('RGB')
+ else:
+ # 8-bit images: convert as needed
+ if img.mode == 'RGBA':
+ # Keep RGBA for transparency support
+ img = img.convert('RGBA')
+ elif img.mode != 'RGB':
+ img = img.convert('RGB')
+
+ # Save with maximum compression
+ # PIL will preserve 16-bit for 'I' mode automatically
+ # For color 16-bit, PIL may convert to 8-bit, but we've preserved the mode
img.save(str(output_path), 'PNG', optimize=True, compress_level=9)
new_size = os.path.getsize(output_path)
savings = original_size - new_size