$user: user who performed the deletion
$reason: reason
+'FileTransformed': When a file is transformed and moved into storage
+$file: reference to the File object
+$thumb: the MediaTransformOutput object
+$tmpThumbPath: The temporary file system path of the transformed file
+$thumbPath: The permanent storage path of the transformed file
+
'FileUpload': When a file upload occurs
$file : Image object representing the file that was uploaded
$reupload : Boolean indicating if there was a previously another image there or not (since 1.17)