Piwigo 2.4 introduces the feature multizise, this includes many technical changes, especially in the filesystem :

Before 2.4 the galleries and upload folders looked like this :

+--Album
  +--pwg_high
  | |-mg_3663.png
  | |-mg_3664.png
  | \-mg_3665.png
  +--thumbnail
  | |-TN-mg_3663.png
  | |-TN-mg_3664.png
  | \-TN-mg_3665.png
  |--mg_3663.png
  |--mg_3664.png
  \--mg_3665.png

Now in 2.4 we keep only one version of each photo (the original file, equivalent to old pwg_high) :

+--Album
  |--mg_3663.png
  |--mg_3664.png
  \--mg_3665.png

The direct consequences are :

• the hotlink on the “web size” becomes a hotlink on the original
• the hotlink on the HD no longer works
• the hotlink on the thumbnail no longer works

To solve this issue Piwigo tries to create or modify the .htaccess file on the root of your installation. This file contains some url rewrite rules informing your host that links to pictures had changed.

If for some reason Piwigo can't create or modify the file you will have to edit it manually. Before do that think if you need it : if you are sure nobody hotlinks your pictures you can just ignore the following steps.

1. First of all, navigate to your Piwigo installation folder with a FTP client
2. If you don't see a file named .htaccess (with the first dot) create it
3. Now open this file with a text editor like Notepad (not complex a editor like Microsoft Word)
4. If it's a previously existing file, be careful there is not RewriteEngine off into it, otherwise you have to modify it into RewriteEngine on or the following will break your website.
5. Add it the .htaccess file these lines with some modifications :
   • on lines 5 and 6 modify thumbnail by the content of your local $conf['dir_thumbnail'] if you have one
   • on lines 5 and 6 modify TN\- by the content of your local $conf['prefix_thumbnail'] if you have one
   • on lines 13 and 15 modify localhost by your hostname without http or www (example: my\-website\.com)
   • CAUTION: if you have hyphens in all these values prepend them with a anti-slash (TN- becomes TN\-), you must also escape dots

<IfModule mod_rewrite.c>
RewriteEngine on

## redirect <2.4 thumbnails hotlinks to i.php
RewriteRule ^upload/(.*)/thumbnail/TN\-(.*)\.([a-z0-9]{3,4})$ i.php?/upload/$1/$2-th.$3 [L]
RewriteRule ^galleries/(.*)/thumbnail/TN\-(.*)\.([a-z0-9]{3,4})$ i.php?/galleries/$1/$2-th.$3 [L]

## redirect <2.4 high-def hotlinks to original file
RewriteRule ^upload/(.*)/pwg_high/(.*)\.([a-z0-9]{3,4})$ upload/$1/$2.$3 [L]
RewriteRule ^galleries/(.*)/pwg_high/(.*)\.([a-z0-9]{3,4})$ galleries/$1/$2.$3 [L]

## redirect <2.4 low-def hotlinks to i.php
RewriteCond %{HTTP_REFERER} !^http://(www\.)?localhost/.*$ [NC]
RewriteRule ^upload/(.*)/(.*)\.([a-z0-9]{3,4})$ i.php?/upload/$1/$2-me.$3 [L]
RewriteCond %{HTTP_REFERER} !^http://(www\.)?localhost/.*$ [NC]
RewriteRule ^galleries(.*)/(.*)\.([a-z0-9]{3,4})$ i.php?/galleries/$1/$2-me.$3 [L]
</IfModule>

1. Now old hotlinks should we correctly redirected