WordPress new logo theme support function

custom-logo.php

/**
 * Display the logo in your theme using the following functions: the_site_logo() and get_the_site_logo()
 * Check if logo exists using the following function: has_custom_logo()
 * The the_site_logo() function output is <a href="%1$s" class="site-logo-link"><img class="site-logo" data-size="%2$s" /></a>. Make sure you use the appropriate CSS classes in your theme Front End.
 * The function has this filter apply_filters( 'get_the_site_logo', $html, $size );
 * Use "site_logo" id in JS to create Customizer Transport
 */
 
/**
 * Check WordPress version
 *
 * @param string $tocheck - WP version you want to check against the current version
 * @return boolean
 */
if(!function_exists('blesk_check_wp_version')) {
    function blesk_check_wp_version($tocheck) {

        //Get current value
        global $wp_version;

        //Check if $tocheck exists, if not the function will return always false
        if(!$tocheck) {
            $tocheck = $wp_version;
        }

        return ($wp_version > $tocheck ? true : false);
    }
}

//This functioon goes in your theme setup function
if(blesk_check_wp_version('4.5')) {
    add_image_size( 'blesk-logo', 276, 83 );
    add_theme_support( 'custom-logo', array( 'size' => 'blesk-logo' ) );
}