js正则表达式如何匹配http~jpg.png.gif格式？

Question

从后台获取的数据如何把图片地址和文字划分开来。var str="好http://mooc-10050339.file.myqcloud.com/userH5/201707/1499306377538.gifhttp://mooc-10050339.file.myqcloud.com/userH5/201707/1499306377538.jpghttp://mooc10050339.file.myqcloud.com/userH5/201707/1499306377538.png好大家好我是好"如何匹配http然后包含gif或png、jpg 渲染到html页面上来如图好 <img src="http://mooc-10050339.file.myqcloud.com/userH5/201707/1499306377538.gif">好大家好我是好