Help Needed Getting URL Shortcode Working Post-4.2.3

Hi, I am using a simple shortcode to output the URL of my site for use in URLs in my theme. e.g:


... img src="[rs-get-site-url]/wp-content/themes/theme_1.0/image.png" alt="" ...


This is the shortcode code, in functions.php:


add_shortcode('rs-get-site-url', 'rs_get_site_url_func');

function rs_get_site_url_func() {
return get_site_url();
}

Since the WordPress 4.2.3 update this has stopped working, but because I am not using bad quotes or variables, I don’t know why. How can I get this working in WordPress 4.2.3?

My site is not working until I get this working again.

Any help appreciated,

Mav3000 ??