diff --git a/src/Controllers/PostController.php b/src/Controllers/PostController.php
index ee5e80b8..8a9bac75 100644
--- a/src/Controllers/PostController.php
+++ b/src/Controllers/PostController.php
@@ -529,12 +529,9 @@ class PostController
 		if (!is_readable($path))
 			throw new SimpleException('Thumbnail file is not readable');
 
-		$ttl = 60 * 60 * 24 * 3;
-		\Chibi\HeadersHelper::set('Pragma', 'public');
-		\Chibi\HeadersHelper::set('Cache-Control', 'public, max-age=' . $ttl);
-		\Chibi\HeadersHelper::set('Expires', gmdate('D, d M Y H:i:s \G\M\T', time() + $ttl));
-
+		$this->context->transport->cacheDaysToLive = 30;
 		$this->context->transport->mimeType = 'image/png';
+		$this->context->transport->fileHash = 'thumb' . $post->file_hash;
 		$this->context->transport->filePath = $path;
 	}
 
@@ -568,13 +565,12 @@ class PostController
 			$ext);
 		$fn = preg_replace('/[[:^print:]]/', '', $fn);
 
-		$ttl = 60 * 60 * 24;
-		\Chibi\HeadersHelper::set('Pragma', 'public');
-		\Chibi\HeadersHelper::set('Cache-Control', 'public, max-age=' . $ttl);
-		\Chibi\HeadersHelper::set('Expires', gmdate('D, d M Y H:i:s \G\M\T', time() + $ttl));
+		$ttl = 60 * 60 * 24 * 14;
 
+		$this->context->transport->cacheDaysToLive = 14;
 		$this->context->transport->customFileName = $fn;
 		$this->context->transport->mimeType = $post->mimeType;
+		$this->context->transport->fileHash = 'post' . $post->file_hash;
 		$this->context->transport->filePath = $path;
 	}
 
diff --git a/src/Views/layout-file.phtml b/src/Views/layout-file.phtml
index 180d64de..7a4f4386 100644
--- a/src/Views/layout-file.phtml
+++ b/src/Views/layout-file.phtml
@@ -6,6 +6,24 @@ if (!empty($this->context->transport->errorMessage))
 }
 else
 {
+	$lastModified = filemtime($this->context->transport->filePath);
+	$eTag = $this->context->transport->fileHash;
+	$ttl = $this->context->transport->cacheDaysToLive * 24 * 3600;
+
+	$ifModifiedSince = isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])
+		? $_SERVER['HTTP_IF_MODIFIED_SINCE']
+		: false;
+
+	$eTagHeader = isset($_SERVER['HTTP_IF_NONE_MATCH'])
+		? trim(trim($_SERVER['HTTP_IF_NONE_MATCH']), '"')
+		: false;
+
+	\Chibi\HeadersHelper::set('ETag', '"' . $eTag . '"');
+	\Chibi\HeadersHelper::set('Last-Modified', gmdate('D, d M Y H:i:s \G\M\T', $lastModified));
+	\Chibi\HeadersHelper::set('Pragma', 'public');
+	\Chibi\HeadersHelper::set('Cache-Control', 'public, max-age=' . $ttl);
+	\Chibi\HeadersHelper::set('Expires', gmdate('D, d M Y H:i:s \G\M\T', time() + $ttl));
+
 	if (isset($this->context->transport->customFileName))
 	{
 		\Chibi\HeadersHelper::set(
@@ -17,6 +35,12 @@ else
 		'Content-Type',
 		$this->context->transport->mimeType);
 
+	if (strtotime($ifModifiedSince) == $lastModified or $eTagHeader == $eTag)
+	{
+		header('HTTP/1.1 304 Not Modified');
+		exit;
+	}
+
 	readfile($this->context->transport->filePath);
 	flush();
 }