Switch to WP_Image_Editor_GD

functions.php

/**
@@ Sửa lỗi Post-Processing of Image Failed WordPress
@@ Sử dụng module GD Library để xử lý hình ảnh Wordpress
**/
function wpb_image_editor_default_to_gd( $editors ) {
    $gd_editor = 'WP_Image_Editor_GD';
    $editors = array_diff( $editors, array( $gd_editor ) );
    array_unshift( $editors, $gd_editor );
    return $editors;
}
add_filter( 'wp_image_editors', 'wpb_image_editor_default_to_gd' );