Remote uploads function

gistfile1.txt

<?php
define( 'LIVE_URL', 'http://yoursite.com')
// add_action('init', 'my_replace_image_urls' );
function my_replace_image_urls() {
	$site_url = get_site_url();
	if ( false !== strpos( $site_url, '.dev' ) ){
		add_filter( 'wp_get_attachment_url', 'replace_dev_url', 10, 2 );
		add_filter( 'wp_calculate_image_srcset', 'replace_dev_url_srcset', 10, 2 );
	}
}

function replace_dev_url( $url, $post_id) {
	$site_url = get_site_url();
	if ( $file = get_post_meta( $post_id, '_wp_attached_file', true) ) {
		if ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) {
			if ( file_exists( $uploads['basedir'] .'/'. $file ) ) {
				return $url;
			}
		}
	}
	return str_replace( $site_url, LIVE_URL, $url );
}

function replace_dev_url_srcset( $sources ) {
	$site_url = get_site_url();
	$filtered_sources = array();
	foreach( $sources as $source_key => $source ) {
		$source['url'] = str_replace( $site_url, LIVE_URL, $source['url']);
		$filtered_sources[$source_key] = $source;
	}
	return $filtered_sources;
}