Just an addition to this: My case i increased image upload size in admin from 120px to 130px which in effect altered my listing carousel from displaying 4 listings to 3 (as images were now bigger.

Now i liked having 4 listings show and to do this i changed:

In plugins/listing_carousel/carousel.listing.tpl
Find:
Code:
Only registered members can view the code.
Change to:
Code:
Only registered members can view the code.
This worked but still displayed 3, but noticed the field section used the same width principal of the upload size so had to also change this:

Same file as above find:
Code:
Only registered members can view the code.
to
Code:
Only registered members can view the code.
Note: If yu notice in the code you are reomving in this second bit there is a +4, so add 4px to the size of the image that you stated in the first code change.

Hope that make sense. And it worked