When working with a lot of images by example for galleries on a website, it could be really interesting to optimize the images to save a lot of space and directly improve the performances of the website and save some traffic if this is limited by your hosting.
Optimize JPEG images with jpegoptim
A great tool to optimize JPEG images is jpegoptim. It's a simple command line tool available as Ubuntu package. You can install it easily :
sudo apt-get install jpegoptim
And it's also really simple to use. First, to optimize an image without loss :
Or with a loss of max 25% :
jpegoptim --max=75 image.jpg
More informations on the official site.
Optimize PNG, BMP and GIF images with optipng
An other tool to optimize other types of images is optipng. Here again you can install it with apt-get :
sudo apt-get install optipng
It's as easy as the first tool :
You can also configure the tool to use the best optimization level, but also the slowest :
optipng -o7 image.png
So here we are : You have now enough informations to optimize all you images on Ubuntu. I hope this will be useful to somebody.