Quick answer: Raise WordPress limits in two places: add WP_MEMORY_LIMIT to wp-config.php for PHP memory, and increase upload_max_filesize, post_max_size, and memory_limit in php.ini (via cPanel MultiPHP INI Editor or Plesk PHP Settings). Keep post_max_size equal to or larger than upload_max_filesize.
WordPress errors like "Allowed memory size exhausted" or a failure to upload larger images usually mean two separate limits need raising: the PHP memory limit and the upload/post size. Here is how to lift both.
Add these lines to wp-config.php, just above the line that says "That's all, stop editing":
define('WP_MEMORY_LIMIT', '256M');
define('WP_MAX_MEMORY_LIMIT', '512M');
WP_MEMORY_LIMIT covers the front end; WP_MAX_MEMORY_LIMIT covers heavier admin tasks like imports. If the server caps PHP below these values, the next step is required too.
These control how large a file you can upload. The cleanest place to set them depends on your stack:
# php.ini upload_max_filesize = 64M post_max_size = 64M memory_limit = 256M max_execution_time = 120
post_max_size must be equal to or larger than upload_max_filesize, or uploads fail silently. On cPanel use the MultiPHP INI Editor; on Plesk use PHP Settings for the domain - both edit these values through a UI.
On some shared setups you can use a .user.ini file in the site root with the same directives, or an .htaccess entry on Apache:
php_value upload_max_filesize 64M php_value post_max_size 64M php_value memory_limit 256M
In WordPress go to Tools > Site Health > Info > Server and check the reported memory limit and max upload size. If they did not change, the value is being overridden at a higher level and your host needs to apply it.
Why do uploads still fail after raising memory?
You also need to raise upload_max_filesize and post_max_size, which control file size separately from memory.
How do I confirm the new limits?
Tools, Site Health, Info, Server shows the active memory limit and max upload size.
On a SoftSys managed WordPress hosting plan these limits are set generously for real-world sites, and we will raise them further on request rather than making you hunt through config files.