必须刷新才能运行功能

I'm trying to create a responsive thumbnail gallery for my portfolio website. .gallerythumb is the thumb, and it's default width is 25%. My jquery, in theory, will resize the width of the thumbnail div containers based on the size of the page. It works, but the if/else statement only runs on page load, meaning I have to refresh the page, after I have resized the browser, to get it to run. Any clue what's going on?I'm trying to create a responsive thumbnail gal