Adjusts the sharpness of image files (PNG, JPG, TIFF and other formats supported
by Pillow). The factor controls the strength: 0.0 produces a completely
blurred (smooth) image, 1.0 leaves the image unchanged, and values above1.0 increase sharpness (a useful range is roughly 0.0–2.0). A factor
of 2.0, for example, noticeably sharpens the image.
Files that are not images are passed through unchanged.