diff --git a/Controller/ManagerController.php b/Controller/ManagerController.php
index e57712c..5faabe2 100644
--- a/Controller/ManagerController.php
+++ b/Controller/ManagerController.php
@@ -289,7 +289,11 @@ public function binaryFileResponseAction(Request $request, string $fileName): Bi
         }
         $this->dispatch(FileManagerEvents::FILE_ACCESS, ['path' => $file]);
 
-        return new BinaryFileResponse($file);
+        $response = new BinaryFileResponse($file);
+        // Last-Modified is set by default; answer revalidation requests with 304 instead of resending the file
+        $response->isNotModified($request);
+
+        return $response;
     }
 
     #[Route("/delete/", name: 'file_manager_delete')]
diff --git a/Resources/doc/book/1-basic-configuration.md b/Resources/doc/book/1-basic-configuration.md
index 7828cc6..56492d6 100644
--- a/Resources/doc/book/1-basic-configuration.md
+++ b/Resources/doc/book/1-basic-configuration.md
@@ -163,7 +163,7 @@ artgris_file_manager:
 | :---  |:--------:|:--------:|:-------------:|
 | `cachebreaker`  | `Boolean` |  False   | True |
 
-Adding a cachebreaker ?time=RANDOM_NUMBER or & &time=RANDOM_NUMBER at the end of the images (preview) url. It's removed if you have used "twig_extension" option.
+Adding a cachebreaker ?time=FILE_MODIFICATION_TIME or &time=FILE_MODIFICATION_TIME at the end of the images (preview) url. The url changes only when the file changes, so the browser can cache previews between page loads. It's removed if you have used "twig_extension" option.
 
 ## `show_file_count` to show the number of files per directory in the file browser tree
 
diff --git a/Service/FileTypeService.php b/Service/FileTypeService.php
index b5a9948..3692634 100644
--- a/Service/FileTypeService.php
+++ b/Service/FileTypeService.php
@@ -34,7 +34,10 @@ public function preview(FileManager $fileManager, SplFileInfo $file) {
         if ('file' === $type) {
             $size = $this::IMAGE_SIZE[$fileManager->getView()];
 
-            return $this->fileIcon($filePath, $extension, $size, true, $fileManager->getConfigurationParameter('twig_extension'), $fileManager->getConfigurationParameter('cachebreaker'));
+            // The modification time keeps the URL stable until the file changes, so the browser can cache it
+            $cachebreaker = $fileManager->getConfigurationParameter('cachebreaker') ? $file->getMTime() : null;
+
+            return $this->fileIcon($filePath, $extension, $size, true, $fileManager->getConfigurationParameter('twig_extension'), $cachebreaker);
         }
         if ('dir' === $type) {
 
@@ -68,7 +71,7 @@ public function accept($type): bool|string {
         return $accept;
     }
 
-    public function fileIcon(string $filePath,?string $extension = null, ?int $size = 75, ?bool $lazy = false, ?string $twigExtension = null, ?bool $cachebreaker = null): array {
+    public function fileIcon(string $filePath,?string $extension = null, ?int $size = 75, ?bool $lazy = false, ?string $twigExtension = null, bool|int|null $cachebreaker = null): array {
 
         $imageTemplate = null;
 
@@ -89,7 +92,8 @@ public function fileIcon(string $filePath,?string $extension = null, ?int $size
                 $fileName = $filePath;
                 if ($cachebreaker) {
                     $query = parse_url($filePath, PHP_URL_QUERY);
-                    $time = 'time='.time();
+                    // An int is used as the version (file modification time), true falls back to the current time
+                    $time = 'time='.(\is_int($cachebreaker) ? $cachebreaker : time());
                     $fileName = $query ? $filePath.'&'.$time : $filePath.'?'.$time;
                 }
 
diff --git a/Tests/Controller/CachebreakerTest.php b/Tests/Controller/CachebreakerTest.php
new file mode 100644
index 0000000..6c9920e
--- /dev/null
+++ b/Tests/Controller/CachebreakerTest.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Artgris\Bundle\FileManagerBundle\Tests\Controller;
+
+use Artgris\Bundle\FileManagerBundle\Tests\Fixtures\AbstractTestCase;
+
+class CachebreakerTest extends AbstractTestCase
+{
+    public function setUp(): void
+    {
+        $this->initClient(['environment' => 'cachebreaker']);
+    }
+
+    public function testImagePreviewCachebreakerIsFileModificationTime()
+    {
+        // A fixed date in the past, so a cachebreaker built from time() cannot match by accident
+        touch(__DIR__.'/../Fixtures/web/images/image.png', 1600000000);
+
+        $crawler = $this->getManagerPage();
+        $this->assertSame('/manager/file/image.png?conf=default&time=1600000000', $crawler->filter('img.lazy')->attr('data-src'));
+    }
+
+    public function testFileIsNotResentWhenNotModified()
+    {
+        $image = __DIR__.'/../Fixtures/web/images/image.png';
+        touch($image, 1600000000);
+
+        // Only the 304 path is requested: a 200 guesses the MIME type, which needs ext-fileinfo (missing on the Windows CI)
+        $this->client->request('GET', '/manager/file/image.png?conf=default', [], [], ['HTTP_IF_MODIFIED_SINCE' => gmdate('D, d M Y H:i:s', 1600000000).' GMT']);
+        $this->assertSame(304, $this->client->getResponse()->getStatusCode());
+    }
+}
diff --git a/Tests/Fixtures/App/config/config_cachebreaker.yml b/Tests/Fixtures/App/config/config_cachebreaker.yml
new file mode 100644
index 0000000..d0e42da
--- /dev/null
+++ b/Tests/Fixtures/App/config/config_cachebreaker.yml
@@ -0,0 +1,8 @@
+imports:
+    - { resource: config.yml }
+
+artgris_file_manager:
+    conf:
+        default:
+            dir: "%kernel.project_dir%/Tests/Fixtures/web/images"
+            cachebreaker: true
diff --git a/Tests/Fixtures/web/images/image.png b/Tests/Fixtures/web/images/image.png
new file mode 100644
index 0000000..500c889
Binary files /dev/null and b/Tests/Fixtures/web/images/image.png differ