From c53655d52e70a763ec686ac77ef8c3c64321053a Mon Sep 17 00:00:00 2001
From: hiroshisuga <45039819+hiroshisuga@users.noreply.github.com>
Date: Sat, 11 May 2024 11:08:42 +0900
Subject: [PATCH] [doc] avoid confusion of default presentation (#18103)

* Update docs/docs/administration/customize.md
---
 docs/docs/administration/customize.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/docs/docs/administration/customize.md b/docs/docs/administration/customize.md
index 276b563a7f..ecb36bef59 100644
--- a/docs/docs/administration/customize.md
+++ b/docs/docs/administration/customize.md
@@ -881,7 +881,7 @@ $ sudo bbb-conf --restart
 
 #### Change the default presentation
 
-When a new meeting starts, BigBlueButton displays a default presentation. The file for the default presentation is located in `/var/www/bigbluebutton-default/assets/default.pdf`. You can replace the contents of this file with your presentation. Whenever a meeting is created, BigBlueButton will automatically load, convert, and display this presentation for all users.
+When a new meeting starts, BigBlueButton displays a default presentation. The file for the default presentation is located in `/var/www/bigbluebutton-default/assets/default.pdf`. You can replace the contents of this file with your presentation. Whenever a meeting is created, BigBlueButton will automatically load, convert, and display this presentation for all users. Note that this file may be overwritten when BigBlueButton is upgraded. 
 
 Alternatively, you can change the global default by adding an overwriting rule in `/etc/bigbluebutton/bbb-web.properties` specifying the URL for `beans.presentationService.defaultUploadedPresentation`.
 
@@ -890,7 +890,9 @@ Alternatively, you can change the global default by adding an overwriting rule i
 beans.presentationService.defaultUploadedPresentation=${bigbluebutton.web.serverURL}/default.pdf
 ```
 
-You'll need to restart BigBlueButton after the change with `sudo bbb-conf --restart`.
+Please use the file name "default.pdf" if you would not like BigBlueButton to generate thumbnails from this file. The thumbnails will be used in some frontend apps, such as Greenlight.
+
+You'll need to restart BigBlueButton after the change with `sudo bbb-conf --restart`. 
 
 If you want to specify the default presentation for a given meeting, you can also pass a URL to the presentation as part of the [create](/development/api#pre-upload-slides) meeting API call.