Keep metadata of image optimized by mozjpeg_lossless_optimization, with piexif

gistfile1.py

import mozjpeg_lossless_optimization
import piexif

src_file = "source_image.jpg"
out_file = "optimized.jpg"

# Open image
with open(src_file, "rb") as input_jpeg_file:
	input_jpeg_bytes = input_jpeg_file.read()

# Get exif data (to dict)
exif_dict = piexif.load(input_jpeg_bytes)

# Optional : this removes the thumbnail from EXIF data
th = exif_dict.pop("thumbnail")

# Image optimization
output_jpeg_bytes = mozjpeg_lossless_optimization.optimize(input_jpeg_bytes)

# Converts the exif dict to bytes
exif_bytes = piexif.dump(exif_dict)

# Optimized image is saved with "old" exif data, by piexif.
piexif.insert(exif_bytes, output_jpeg_bytes, out_file)