手机尺寸
iPhone4 :640 *960 / 320 *480
iPhone4 微信:640 *832 / 320 *416
iPhone5 :640 *1136 / 320 *568
iPhone5 微信:640 *1008 / 320 *504
iPhone6 :750 *1334 / 375 *667
iPhone6 微信:750 *1206 / 375 *603
iPhone6P :1242*2208 / 414 *736
iPhone6P微信:1242*2016 / 414 *672