imgur-gifv-to-gif.user.js

// ==UserScript==
// @name        imgur GIFV to GIF
// @description Turn imgur GIFV links into GIF.
// @exclude     *imgur.com*
// @version     1.0
// @grant       none
// @run-at      document-start
// ==/UserScript==	

(function () {

	var imgur_regex = /^https?:\/\/i\.imgur\.com\/[A-Za-z0-9]+.gifv$/
	var result2 = imgur_regex.exec(window.location);
	
	function replace_links() {
		var links = document.getElementsByTagName('a');
		
		for (var i = 0; i < links.length; i++) {
			var item = links[i];
			result2 = imgur_regex.exec(item.href);
			if (result2) {
				item.href = item.href.slice(0, -1);
			}
		}
	}

	window.addEventListener("DOMContentLoaded", replace_links, false);

}());