[Guide] Expanding WordPress Multisite Upload Capacity to 256MB

This is a comprehensive ‘Full-Stack’ configuration guide to resolve upload limits restricted to 1MB or 2MB in WordPress (especially Docker-based Multisite) environments. It consists of 5 essential steps, from the server engine to application settings.

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1. PHP Configuration (PHP-FPM Environment)

This is the cleanest way to override PHP settings in a Docker environment.

– Filename: .user.ini
– Path: /var/www/html/ (WordPress root directory)

upload_max_filesize = 256M
post_max_size = 256M
memory_limit = 512M
max_execution_time = 600

Security Tip: To prevent external access to your .user.ini file via a browser, add the following code to the top of your .htaccess file:

> <Files ".user.ini">
>     Require all denied
> </Files>
> 

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2. Forced WordPress Runtime Allocation (wp-config.php)

When server configurations are ignored, this method forcibly injects PHP settings at the time WordPress initializes.

– Filename: wp-config.php
– Placement: Insert at the very top, immediately below the <?php tag.

@ini_set( 'upload_max_size' , '256M' );
@ini_set( 'post_max_size', '256M' );
@ini_set( 'memory_limit', '512M' );
@ini_set( 'max_execution_time', '300' );

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3. Web Server Level Configuration (.htaccess)

These settings apply when the Apache server processes requests.

– Filename: .htaccess
– Caution: Write these outside the # BEGIN WordPress and # END WordPress blocks to prevent them from being overwritten during WordPress updates.

# --- PHP Upload Limits Start ---
php_value upload_max_filesize 256M
php_value post_max_size 256M
php_value memory_limit 512M
php_value max_execution_time 600
php_value max_input_time 600
# --- PHP Upload Limits End ---

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4. Multisite Network Settings (The Core Solution)

In a Multisite environment, the Network Admin settings take precedence over all server-level configurations.

1. Navigate to My Sites > Network Admin > Settings.
2. Locate the Max upload file size field.
3. Change the value to 262144 (KB unit, equivalent to 256MB) and save.

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5. Nginx Reverse Proxy Configuration (Mandatory)

By default, Nginx blocks requests exceeding 1MB. If you are using Nginx or a Reverse Proxy (e.g., Synology) in front of your server, this step is mandatory.

– Configuration: Inside the http or server block.

client_max_body_size 256M;

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✅ Final Verification

After completing all settings, restart the container (docker restart) and check the “Maximum upload file size: 256 MB” message under the Media > Add New menu.

docker restart [wordpress_container_name]

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Author: MASTER
Date: 2026-04-10