Still useful after WordPress 4.4 and SUPERB support!

The current WordPress responsive image implementation only inserts srcsets for your images when the aspect ratio differs by less than 0.002.

If you wish to insert srcsets where the images’ aspect ratios differ by greater than 0.002, this plugin is a must! If you theme already creates a ton of image sizes and you don’t want to waste them this plugin is for you.

The rwp_add_filters filter with the included snippet in the documentation allows you to apply the srcsets to images used by other plugins and widgets.

Further, the author provides fantastic support on the forums – bugs are fixed quick.

This is a great plugin with great support!