diff --git wp-includes/media.php wp-includes/media.php
index 9f35f79..e54a5da 100644
--- wp-includes/media.php
+++ wp-includes/media.php
@@ -1109,7 +1109,7 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
 		if ( abs( $constrained_size[0] - $expected_size[0] ) <= 1 && abs( $constrained_size[1] - $expected_size[1] ) <= 1 ) {
 			// Add the URL, descriptor, and value to the sources array to be returned.
 			$source = array(
-				'url'        => $image_baseurl . $image['file'],
+				'url'        => $image_baseurl . str_replace(' ', '%20', $image['file']),
 				'descriptor' => 'w',
 				'value'      => $image['width'],
 			);