How to compress photo size

Most tidy -> webp

via: https://developers.google.com/speed/webp

Download via: https://developers.google.com/speed/webp/docs/precompiled

$ sudo apt install webp
$ cwebp -q 50 -lossless picture.png -o picture_lossless.webp
$ cwebp -q 70 picture_with_alpha.png -o picture_with_alpha.webp
$ cwebp -sns 70 -f 50 -size 60000 picture.png -o picture.webp
$ cwebp -o picture.webp picture.png

JEPG -> jpegoptim

jpegoptim --size=1024k xxx.jpg

• Convert image to JPEG using https://imagemagick.org
• Convert image to JPEG using https://github.com/mozilla/mozjpeg

PNG

(lossy compress) pngquant

via: https://pngquant.org/

optipng

via: https://optipng.sourceforge.net/

a PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections."

用 optipng 壓縮過的圖片合成 == 未用 optipng 壓縮過的圖片合成（對比兩個文件的哈希值都一樣）

optipng -o3 image.png -out output.png

Source via: https://note.bgzo.cc/how-to/compress-photo-size