Use subdirectories in the generated gallery

JavaScript files are now in js/, CSS files in css/, thumbnail images in
thumbnails/.

data/website_gallery/index.html

@@ -4,8 +4,8 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
     <meta name="viewport" content="width=device-width, height=device-height, initial-scale=1.0">
-    <link rel="stylesheet" href="modal.css">
-    <link rel="stylesheet" href="gallery.css">
+    <link rel="stylesheet" href="css/modal.css">
+    <link rel="stylesheet" href="css/gallery.css">
     <title id="page-title">Image Gallery</title>
 
 
@@ -37,9 +37,9 @@
     <script type='text/javascript' >
         var currentIndex = 1;
     </script>
-    <script src="images.js"></script>
-    <script src="fullscreen.js"></script>
-    <script src="modal.js"></script>
-    <script src="gallery.js"></script>
+    <script src="js/images.js"></script>
+    <script src="js/fullscreen.js"></script>
+    <script src="js/modal.js"></script>
+    <script src="js/gallery.js"></script>
 </body>
 </html>

data/website_gallery/js/gallery.js

@@ -66,7 +66,7 @@ document.addEventListener('DOMContentLoaded', function () {
 
         const img = document.createElement('img');
         img.className = 'thumb';
-        img.src = imageObj.filename.replace(/images\/(.*)$/i, 'images/thumb_$1');
+        img.src = imageObj.filename.replace(/images\/(.*)$/i, 'thumbnails/thumb_$1');
         img.alt = imageObj.filename;
         img.addEventListener('click', function (e) { e.stopPropagation(); showModal(e); });