In IP 3 thumbnail image attachments made better use of space.
 They used a horizontal layout and now IP4 stacks them all one above the other.

I really preferred IP3 as it had less scrolling and dead white space in the post.

Anyway to bring this formatting back?

Anybody have a work around?

anyone know how to tweak the CSS to fix this?

I totally agree.  

The vertical layout is a massive and inefficient use of space.  

 

+1 on this. We are an image community and it makes pages endlessly long. 

A good starting point would be the following:

.ipsImage_thumbnailed{
 float:left;
}

Might need some additional work to get things aligning due to the p tags around each a/img combination.