BTW. For me this site is showing all banners in 234x60. I don't really get what you mean with 156x40.
At 100% zoom, this is what I see:
(...)
The banners are 156x40.
I tried making the browser window huge, but it doesn't make the banners any bigger.
Edit: here it is in chromium's "inspect element":
(...)
For me 234x60
-When I save image from this page - 234x60
-When I am taking a screenshot and pasting into PS and measuring it - 234x60.
-In their source:
<td id="n1" class="start"><strong><a target="_blank" href="http://just-dice.com"><img src="https://i.imgur.com/mis0mlF.gif"/></a></strong></td>
https://i.imgur.com/mis0mlF.gif" - link to an 234x60.
For me it is working fine under Opera.
---Update---
Oh my bad sorry, I though that I checked it under Chrome but when I double checked it it came that under Chrome it is indeed 156x40.
Admins need to fix the problem in cascading those tables. Shouldn't be hard.
Simple walk-around: install Opera
Kind regards.