diff --git a/wp-includes/media.php b/wp-includes/media.php
index 63cdfbda8d..a6af7f7f84 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -462,7 +462,8 @@ function image_resize( $file, $max_w, $max_h, $crop = false, $suffix = null, $de
 			return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
 	} else {
 		// all other formats are converted to jpg
-		$destfilename = "{$dir}/{$name}-{$suffix}.jpg";
+		if ( 'jpg' != $ext && 'jpeg' != $ext )
+			$destfilename = "{$dir}/{$name}-{$suffix}.jpg";
 		if ( !imagejpeg( $newimage, $destfilename, apply_filters( 'jpeg_quality', $jpeg_quality, 'image_resize' ) ) )
 			return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
 	}