framework/validators/FileValidator.php
public function getSizeLimit()
    {
        // Get the lowest between post_max_size and upload_max_filesize, log a warning if the first is < than the latter
        $limit = $this->sizeToBytes(ini_get('upload_max_filesize'));
        $postLimit = $this->sizeToBytes(ini_get('post_max_size'));
        if ($postLimit > 0 && $postLimit < $limit) {
            Yii::warning('PHP.ini\'s \'post_max_size\' is less than \'upload_max_filesize\'.', __METHOD__);
            $limit = $postLimit;
        }
        if ($this->maxSize !== null && $limit > 0 && $this->maxSize < $limit) {
            $limit = $this->maxSize;
        }
        if (isset($_POST['MAX_FILE_SIZE']) && $_POST['MAX_FILE_SIZE'] > 0 && $_POST['MAX_FILE_SIZE'] < $limit) {
            $limit = (int) $_POST['MAX_FILE_SIZE'];
        }

        return $limit;
    }
public function getSizeLimit()
    {
        // Get the lowest between post_max_size and upload_max_filesize, log a warning if the first is < than the latter
        $limit = $this->sizeToBytes(ini_get('upload_max_filesize'));
        $postLimit = $this->sizeToBytes(ini_get('post_max_size'));
        if ($postLimit > 0 && $postLimit < $limit) {
            Yii::warning('PHP.ini\'s \'post_max_size\' is less than \'upload_max_filesize\'.', __METHOD__);
            $limit = $postLimit;
        }
        if ($this->maxSize !== null && $limit > 0 && $this->maxSize < $limit) {
            $limit = $this->maxSize;
        }
        if (isset($_POST['MAX_FILE_SIZE']) && $_POST['MAX_FILE_SIZE'] > 0 && $_POST['MAX_FILE_SIZE'] < $limit) {
            $limit = (int) $_POST['MAX_FILE_SIZE'];
        }

        return $limit;
    }
Returns the maximum size allowed for uploaded files.

This is determined based on four factors:

- 'upload_max_filesize' in php.ini
- 'post_max_size' in php.ini
- 'MAX_FILE_SIZE' hidden field
- [[maxSize]]

@return int the size limit for uploaded files.