Maximizing the full capacity of Jetpack, I decided to enable Photon to boost serving of images in my blog from WordPress.com end. It’s worth noting that WordPress.com rank very well in terms of DNS performance.

Along the way of discovering how to effectively use this module to match with the design specification of my blog, I have discovered few things to be mindful of.

Caching

Images are cached like forever. If you decided to update the image, renaming would be the solution.

Shrinking

If you experience shrinking or if it’s not serving the dimension you set, consider checking your theme functions.php for something like this code:

if ( ! isset( $content_width ) )
    $content_width = 640; /* pixels */

Add the code if there’s nothing similar to that in the file yet. Change the $content_width to the maximum width of an image you’re serving up. Photon can perfectly handle resizing of image to lower resolution but it will not upscale an image in most circumstances.

Retina

You will love this module even more for it’s capability to support retina devices out of the box!