Ciao,
I write


in the theme.
The language switch works perfectly!
But I don't know where and with which name should I put the langimages.
Could you kindly advice me?
Thanks.
Look into XOOPS_ROOT_PATH/include/easiestml.php line 11 you will see how langimages are defined. Note that "images" there is a relative path for "XOOPS_ROOT_PATH/images"
Put your images (for example francais.gif for French) under XOOPS_ROOT_PATH/images then change the line above to something like this:
define('EASIESTML_LANGIMAGES','images/english.gif,images/francais.gif');
You may wish to change other constants inside the easiestml.php to meet your need too.