Manual.rst: add notes for 'fileSplit'

extension/Documentation/Manual.rst

@@ -3834,7 +3834,12 @@ Split PDF Upload
 """"""""""""""""
 
 Additional to the upload, it's possible to split the uploaded file (only PDF files) into several SVG or JPEG files, one
-file per PDF page. The split is done via http://www.cityinthesky.co.uk/opensource/pdf2svg/ or Image Magick `convert`.
+file per PDF page. The split is done via a) http://www.cityinthesky.co.uk/opensource/pdf2svg/ or b) Image Magick `convert`.
+
+Currently, QFQ can only split PDF files.
+
+If the source file is not of type PDF, activating ``fileSplit`` has no impact: no split and NO complain about invalid
+file type.
 
  * *FormElement.parameter*:
 

extension/Source/core/Save.php

@@ -936,6 +936,8 @@ class Save {
      */
     private function splitUpload(array $formElement, $pathFileName, $chmod, array $statusUpload) {
 
+
+        // Should the file be split and it's technically possible to split the file?
         if (empty($formElement[FE_FILE_SPLIT]) || $statusUpload[FILES_TYPE] != MIME_TYPE_SPLIT_CAPABLE) {
             return;
         }