diff --git a/wp-includes/media.php b/wp-includes/media.php
index fe907de4a..425840de9 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -259,7 +259,7 @@ function wp_constrain_dimensions( $current_width, $current_height, $max_width=0,
  * @param bool $crop Optional, default is false. Whether to crop image or resize.
  * @return bool|array False, on failure. Returned array matches parameters for imagecopyresampled() PHP function.
  */
-function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop=false) {
+function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = false) {
 
 	if ($orig_w <= 0 || $orig_h <= 0)
 		return false;
@@ -272,22 +272,23 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop=false
 		$aspect_ratio = $orig_w / $orig_h;
 		$new_w = min($dest_w, $orig_w);
 		$new_h = min($dest_h, $orig_h);
-		if (!$new_w) {
+
+		if ( !$new_w ) {
 			$new_w = intval($new_h * $aspect_ratio);
 		}
-		if (!$new_h) {
+
+		if ( !$new_h ) {
 			$new_h = intval($new_w / $aspect_ratio);
 		}
 
 		$size_ratio = max($new_w / $orig_w, $new_h / $orig_h);
 
-		$crop_w = ceil($new_w / $size_ratio);
-		$crop_h = ceil($new_h / $size_ratio);
+		$crop_w = round($new_w / $size_ratio);
+		$crop_h = round($new_h / $size_ratio);
 
-		$s_x = floor(($orig_w - $crop_w)/2);
-		$s_y = floor(($orig_h - $crop_h)/2);
-	}
-	else {
+		$s_x = floor( ($orig_w - $crop_w) / 2 );
+		$s_y = floor( ($orig_h - $crop_h) / 2 );
+	} else {
 		// don't crop, just resize using $dest_w x $dest_h as a maximum bounding box
 		$crop_w = $orig_w;
 		$crop_h = $orig_h;
@@ -299,12 +300,12 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop=false
 	}
 
 	// if the resulting image would be the same size or larger we don't want to resize it
-	if ($new_w >= $orig_w && $new_h >= $orig_h)
+	if ( $new_w >= $orig_w && $new_h >= $orig_h )
 		return false;
 
 	// the return array matches the parameters to imagecopyresampled()
 	// int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h
-	return array(0, 0, $s_x, $s_y, $new_w, $new_h, $crop_w, $crop_h);
+	return array( 0, 0, $s_x, $s_y, $new_w, $new_h, $crop_w, $crop_h );
 
 }