Pictures' opacity when they're hovered and few more questions.

Hi there. ; ))
So what's the code to make pictures in sub-categories' descriptions change their opacity when they're hovered?
The other question is how to make the forum description to go over the logo?
And is it possible the navbar to go on the top of the logo in phpbb3 or it's just possible in punbb and phpbb2?
edit: and how can i make the widgets to be like this >>

SCREENSHOT:

Thanks in advance.

Bump.

Bump ...

Thanks cool info.