Inital implementation of image listing

Output.php

@@ -38,6 +38,40 @@ class Output
         }
     }
 
+    /**
+     * Render a thumbnail gallery (XHTML only).
+     *
+     * Expects a flat list of file items in $this->files.
+     * Clicking a thumbnail opens the original image.
+     *
+     * @param array $params
+     * @return void
+     */
+    public function renderAsGallery($params)
+    {
+        if (!($this->renderer instanceof \Doku_Renderer_xhtml)) {
+            $params['style'] = 'list';
+            $this->renderAsList($params);
+            return;
+        }
+
+        /** @var \Doku_Renderer_xhtml $renderer */
+        $renderer = $this->renderer;
+        $renderer->doc .= '<div class="filetools-plugin filetools-gallery">';
+
+        foreach ($this->files as $item) {
+            $url = $this->itemWebUrl($item, !empty($params['randlinks']));
+            $safeUrl = hsc($url);
+            $label = hsc($item['name']);
+
+            $renderer->doc .= '<a href="' . $safeUrl . '" class="media" title="' . $label . '">';
+            $renderer->doc .= '<img src="' . $safeUrl . '" alt="' . $label . '" width="150" loading="lazy" />';
+            $renderer->doc .= '</a>';
+        }
+
+        $renderer->doc .= '</div>';
+    }
+
     /**
      * Renders the files as a table, including details if configured that way.
      *