Hello,
Using 3.0 we configured our site logo (image) for use with Xerte. The logo didn't appear on the login page, but did appear once logged in. The image was put into the 'branding' directory as 'logo_right.png'.
The browser console showed the problem to be an incorrect URL. In our case:
http://.../var/www/html/xerte/branding/logo_right.png [HTTP/1.1 404 Not Found 1ms]
Looking at the file 'website_code/php/login_library.php' shows that both the left and right logos are checked for existence, and then tried to be loaded with the full disk pathname. This obviously fails.
I have attached a patch for this which worked for us.