If WordPress show a message error “Fatal error: Allowed memory size”, for example to add a picture or installing a new plugin in your wordpress account. This is because you are exceeded memory limit reserved to PHP and you need increase it. I propose different solutions.

Wordpress error "Fatal error: Allowed memory size"

Solution at WordPress error «Fatal error: Allowed memory size»

Login via FTP client (Filezilla for example) to your hosting account and try to solve the problem
with one of the following solutions:

  1. Edit wp-config.php file, the file is in the blog root folder and add at the end define(‘wp_memory_limit’,’XXM’); where XXM is the amount of memory you need:
    /** WordPress absolute path to the WordPress directory. */if ( !defined('ABSPATH') )
    define('ABSPATH', dirname(__FILE__) . '/');
    /** Sets up WordPress vars and included files. */require_once(ABSPATH . 'wp-settings.php');
    
    define('wp_memory_limit','80M');

    If you don’t solve the problem, try with define(‘WP_MAX_MEMORY_LIMIT’, ‘XXM’)

    /** WordPress absolute path to the WordPress directory. */if ( !defined('ABSPATH') )
    define('ABSPATH', dirname(__FILE__) . '/');
    /** Sets up WordPress vars and included files. */require_once(ABSPATH . 'wp-settings.php');
    
    define('WP_MAX_MEMORY_LIMIT', '80M');
  2. Edit .htaccess file, this file is in the blog root folder (probably hidden)
    and add the code line php_value memory_limit XXM:
    <IfModule mod_rewrite.c>
    php_value memory_limit 64M
    RewriteEngine On
    RewriteBase /
    RewriteRule ^index\.php$ - [L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /index.php [L]
    </IfModule>
  3. Try to increase a memory specified in the default-constants.php file,
    this file find it in wp-includes folder. Edit line 9 where in the example
    is define(‘WP_MEMORY_LIMIT’, ’48M’); and especified increasing the memory you need:
    function wp_initial_constants() {
    global $blog_id;
    
    // set memory limits
    if ( !defined('WP_MEMORY_LIMIT') ) {
    if( is_multisite() ) {
    define('WP_MEMORY_LIMIT', '64M');
    } else {
    define('WP_MEMORY_LIMIT', '48M');
    }
    }
    
    if ( ! defined( 'WP_MAX_MEMORY_LIMIT' ) ) {
    define( 'WP_MAX_MEMORY_LIMIT', '256M' );
    }

    If your wordpress install is multisite, then modify line 7 where in the example is define(‘WP_MEMORY_LIMIT’, ’64M’);