Workaround for JetPack site accelerators causing full-size images to shrink when enabled

Sep 6, 2020 PHP WordPress Jetpack


When JetPack’s Site Accelerator </ q> and Speed up static file loading </ q> are turned on in WordPress, the width of the image loaded in the post will be reduced. Image size </ q>: Even if you specify Full size </ q>, it will be reduced to 1024px.


JetPack refers to global $ content_width to determine the maximum width of the image 1.

How to solve

Add the following contents to functions.php etc. and overwrite $ global $ content_width 2.

<? php
// ...

(function () {
global $ content_width;
$ content_width = 1920; // Specify the maximum expected width of the image.
}) ();

// ...


In the future 3, it may be possible to change global $ content_width withadd_theme_support ()4.

Reference page

  1. Therefore, if global $ content_width is specified in the theme, it may be a width other than 1024px. ↩︎

  2. The specification in the child theme or plugin has not been verified. You may need to use add_action ('after_setup_theme', $ function_to_add). ↩︎

  3. The latest WordPress version at the time of this writing is 5.5.1. ↩︎

  4. Cf. # 21256 (New theme feature –add_theme_support (‘content-width’, $ defaults)) – WordPress Trac. ↩︎