iOS 上传图片压缩大小设置

+(NSData *)imageData:(UIImage *)myimage
{
    NSData *data=UIImageJPEGRepresentation(myimage, 1.0);
    
    if (data.length>1024 *1024) {
        if (data.length>10240*1024) {//10M以及以上
            data=UIImageJPEGRepresentation(myimage, 0.1);//压缩之后1M~
        }else if (data.length>5120*1024){//5M~10M
            data=UIImageJPEGRepresentation(myimage, 0.2);//压缩之后1M~2M
        }else if (data.length>2048*1024){//2M~5M
            data=UIImageJPEGRepresentation(myimage, 0.5);//压缩之后1M~2.5M
        }
        //1M~2M不压缩
    }
    return data;
}