If you were watching closely, you may have noticed that we recently introduced the option for lossy JPEG compression with Photon. The new parameters are quality and strip. Quality is pretty straight forward — the image quality out of 100. Strip refers to meta data that can be stripped from an image — namely exif and color data. It accepts exif
, color
, or all
for both.
For example: https://developer.files.wordpress.com/2015/02/dsc01921.jpg?w=780&quality=80&strip=all
You can drop a snippet like this in a plugin to set the quality and strip parameters for every image on the site.
add_filter('jetpack_photon_pre_args', 'jetpackme_custom_photon_compression' ); function jetpackme_custom_photon_compression( $args ) { $args['quality'] = 80; $args['strip'] = 'all'; return $args; }
The results can be pretty dramatic. At full size, this image of downtown Madison goes from 16MB to 2.7MB by setting the quality to 80%. That’s a big deal on a mobile connection and it’s pretty hard to spot the difference on most images unless you’re looking at them side by side.
Awesome news. And how this impact on DPI of images when it comes to preserve this value but still wanting to reduce its weight?
Same resolution and DPI.
Of all the parameters, these are my favorite.