How to prevent a menu list from going down off screen

Hi all,
I’m trying to make a menu in which the 3rd level is composed of only pictures linking to pages of my site.
The problem is that since the images will be 150px high, if I put more than 4 or 5 the menu goes off screen. Is there a way to prevent this by forcing the items to stay on screen, perhaps by forming a new column when they get to the bottom of the screen? Or is this kind of thing only possible in javascript?
For info here’s a link to the page , the menu with the photos is the left sidebar:
Category4 –> Language
Thanks in advance for your advice

HI, doing multi column layoust are possible in CSS3 but not with pure CSS> Your best bet would be try to accomodate for this by setting up 3/4 columns already in the page (unles you want to manually go to each gallery page and set teh amount of columns you will need :))

Thanks for this incredibly fast answer Ryan.
You mean I could preset columns in the 3rd level of my menu?
I found this menu by Stu Nicholls, is this what you meant by setting columns?

If that’s the kind of menu you wanted (aka that type of dropdown) then I completely misunderstood lol :).

That menu is fine, use that if you please.