Wordpress upload limit

upload-limit.php

function upload_limits($file) {

    $size = $file['size'];
    $size = $size / 1024;

    $type = $file['type'];
    
    $is_image = strpos( $type, 'image' ) !== false;
    
    $limit = 250;
    $limit_output = '250kb';

    if ( $is_image && $size > $limit ) {
        $file['error'] = 'Image files must be smaller than ' . $limit_output;
    }
    return $file;
}

add_filter( 'wp_handle_upload_prefilter', 'upload_limits' );