/**
* WP 4.4 introduces automatic responsive image generation. Although very useful, for some sites it is not necessary.
*
* As official supporter of "Options, not Decisions", this filter is perfect to give you the option to turn this feature off.
*
* @source: //linkedin.com/grp/post/1482937-6069874958148923392
*/
remove_filter( 'the_content', 'wp_make_content_images_responsive' );