Quote by suvi: Is it possible to configure the elements of {plg_menu_elements} ?
Nope. Have a look at the "custom" entry and function CUSTOM_menuEntries in lib-custom.php
Quote by suvi: How to change the logo from logo.png to logo.jpg ?
{site_logo} is just a hard-coded shortcut for {layout_url}/images/logo.gif
Actually, in 1.4 you could set the global variable $_IMAGE_TYPE to 'jpg' and then it would be logo.jpg - but all your other images would also have to be JPGs then.
So, using {layout_url}/images/logo.jpg as a replacement for {site_logo} is probably the better idea.
bye, Dirk