Gaps in Masonry Flat Portfolio

Hi,

I'm having an issue with Masonry Flat | 4 Columns. Basically, when the page loads itself up, I get small margins in between each portfolio item - they don't sit up next to each other nicely.

If I resize my browser window, they will then snap together and look perfect, it's just that they won't do that unless I resize the window.

I am using a hosts file on my computer to map the hostname to the new server's IP address, so if I am able to send you a file in a private message, then you will be able to view the website to get a better idea?

Thanks.