Added

• Output grayscale JPEGs when possible. These are smaller than color JPEGs.
• Add background color if output format doesn't support transparency. Set the background color using --background-color option.
• Handle Exif orientation of input file. Rotate and flip the image data accordingly.
• Add --spread option to configure quality spread. For example --quality 80 --spread 10 will target JPEG quality of 80 with the minimum quality of 70 and maximum quality of 90.

Changed

• Enable WebP sharp YUV option. This results in sharper images with a bit of additional processing time and file size. For more information, see https://www.ctrl.blog/entry/webp-sharp-yuv.html

Removed

• --input-format option is not needed anymore because input format is automatically detected based on magic number.

Fixed

• Support non-UTF-8 filenames