image-grayscale-conversion

name	image-grayscale-conversion
description	Convert RGB color images to grayscale and save them in-place, overriding the original files. Use this skill whenever the user asks to convert images to gray-scale, desaturate photos, or prepare images for grayscale processing pipelines using OpenCV or Pillow.

In-Place Image Grayscale Conversion

Convert one or more color (RGB) images to grayscale, overwriting the original files.

Using OpenCV (recommended)

import cv2
import glob

image_paths = sorted(glob.glob('/root/keyframes_*.png'))
for path in image_paths:
    img = cv2.imread(path)
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    cv2.imwrite(path, gray)

• cv2.imread loads image as BGR by default.
• cv2.COLOR_BGR2GRAY converts to single-channel grayscale.
• cv2.imwrite saves back to the same path, overwriting the original.

Using Pillow

from PIL import Image
img = Image.open(path).convert('L')
img.save(path)

Notes

• After conversion the file is a single-channel (8-bit) PNG — verify with cv2.imread(path).shape which should show (H, W) instead of (H, W, 3).
• Grayscale images are required for many template-matching and feature-detection algorithms.