Smush Stopped Working On Latest Update

To return to earlier version, you can manually download and install it from https://wordpress.org/plugins/wp-smushit/developers/

You need to edit wp-config.php, and add the code

// Enable WP_DEBUG mode
define('WP_DEBUG', true);

// Enable Debug logging to the /wp-content/debug.log file
define('WP_DEBUG_LOG', true);

// Disable display of errors and warnings
define('WP_DEBUG_DISPLAY', false);
@ini_set('display_errors',0);

Here is the ref: https://codex.wordpress.org/Debugging_in_WordPress#Example_wp-config.php_for_Debugging

After that, you’ll find a file debug.log in wp-content folder, you have to check that file for any smush related errors. Make sure you remove the above code, later on, so that it doesn’t fill up the debug file with big chunk.

Cheers