diff --git a/core/extension.php b/core/extension.php
index 65d90694..82c939cd 100644
--- a/core/extension.php
+++ b/core/extension.php
@@ -325,6 +325,7 @@ abstract class DataHandlerExtension extends Extension
                 $event->metadata['tags'] = $existing->get_tag_list();
 
                 $image = $this->create_image_from_data(warehouse_path(Image::IMAGE_DIR, $event->hash), $event->metadata);
+                $image->posted = $existing->posted;
                 send_event(new ImageReplaceEvent($event->replace_id, $image));
                 $_id = $event->replace_id;
                 assert(!is_null($_id));
diff --git a/ext/upload/test.php b/ext/upload/test.php
index be099ba6..56347e16 100644
--- a/ext/upload/test.php
+++ b/ext/upload/test.php
@@ -56,6 +56,9 @@ class UploadTest extends ShimmiePHPUnitTestCase
 
         $this->log_in_as_admin();
         $image_id = $this->post_image("tests/pbx_screenshot.jpg", "pbx computer screenshot");
+        $original_posted = $database->get_one("SELECT posted FROM images WHERE id = $image_id");
+
+        sleep(1); // make sure the timestamp changes (see bug #903)
 
         $_FILES = [
             'data' => [
@@ -70,8 +73,13 @@ class UploadTest extends ShimmiePHPUnitTestCase
         $page = $this->post_page("replace/$image_id");
         $this->assert_response(302);
         $this->assertEquals("/test/post/view/$image_id", $page->redirect);
+        $new_posted = $database->get_one("SELECT posted FROM images WHERE id = $image_id");
 
         $this->assertEquals(1, $database->get_one("SELECT COUNT(*) FROM images"));
+
+        // check that the original timestamp is left alone, despite the
+        // file being replaced (see bug #903)
+        $this->assertEquals($original_posted, $new_posted);
     }
 
     public function testUpload()