会根据不同设备打包出不同的指定包
arm64:iPhone6s | iphone6s plus|iPhone6| iPhone6 plus|iPhone5S | iPad Air| iPad mini2(iPad mini with Retina Display)
armv7s:iPhone5|iPhone5C|iPad4(iPad with Retina Display)
armv7:iPhone4|iPhone4S|iPad|iPad2|iPad3(The New iPad)|iPad mini|iPod Touch 3G|iPod Touch4
可视情况而定适当放弃部分手机的支持
1、压缩,使用imageOpitm等软件进行图片压缩处理 2、大图不要放到Assets.xcassets中
NSString *path = [[NSBundle mainBundle] pathForResource:@"home_carousel" ofType:@"jpeg"];
img1.image = [UIImage imageWithContentsOfFile:path];