diff --git a/models/Thumbnail.php b/models/Thumbnail.php
index 22987354..46eda451 100644
--- a/models/Thumbnail.php
+++ b/models/Thumbnail.php
@@ -164,6 +164,8 @@ class Thumbnail
 				$this->filename_suffix .= 's';
 			elseif ($this->crop_mode === self::CROP_MODE_SLICE_BOTTOM)
 				$this->filename_suffix .= 'b';
+			elseif ($this->crop_mode === self::CROP_MODE_BOUNDARY)
+				$this->filename_suffix .= 'e';
 		}
 		else
 			$this->filename_suffix = '';