Today we want to recommend a great tools for every webdeveloper that cares about the website speed: jpegoptim and optipng.
Both apps are available in standard repositories of most linux distributions, the usage is very simple:
optipng file.png
optipng *.png
optipng */*.png
optiping *.png -o3 # 3 is compression level, 0-7.
jpegoptim file.jpg
jpegoptim *.jpg
jpegoptim */*.jpg
jpegoptim *.jpg --max=85 # 85 is quality level, 0 - 100
It can really boost the speed of your website, try it out!