Excuse me, I have a problem.
I have changed the name of image on save with the alias and this is ok., but..
I have a problem when there is an accented character in alias.
Don't save the image.

In file /administrator/components/com_k2/models/item.php
I have changed in
$handle->file_new_name_body = $row->alias;
but if in the alias there is "à" or "è" don't save.

str_replace??
Can you help me? thanks

You can use str_replace() php.net/manual/en/function.str-replace.php to remove all unwanted characters.