who needs AI when we have a wonderful package like ffmpeg.

use "convert" part of ffmpeg package

  convert -resize 25% in-file.jpg out-file.jpg

  convert -resize 25% 1.jpeg 1.png

This will reduce the size to 25%, not by 25%.

in-file.jpg 235.5 Kib 1200x1600 -->> out-file.jpg 35.8 Kib 300x400

------------------------------- use mogrify

batch:

  mogrify -resize 25% *.jpg      # keep image aspect ratio
  mogrify -resize 60% *.png      # keep image aspect ratio
  mogrify -resize 320x240 *.png  # keep image aspect ratio

see the !

  mogrify -resize 320x240! *.png # don't keep image aspect ratio
  mogrify -resize x240 *.png     # don't keep image aspect ratio
  mogrify -resize 320x *.png     # don't keep image aspect ratio