error: Not a JPEG file: starts with 0xff 0xd9

通过ASIHttpRequest 下载的图片文件保存到 path 里面

然后

UIImage *myImage = [UIImage imageWithContentsOfFile:path];

然后对 myImage 进行处理或者保存 就会报错，直接导致app crash

http://stackoverflow.com/questions/5081297/ios-uiimagejpegrepresentation-error-not-a-jpeg-file-starts-with-0xff-0xd9

采用上面的处理方式，终于解决了问题

UIImage *myImage = [UIImage imageWithContentsOfFile:path];

to

NSData *img = [NSData dataWithContentsOfFile:path];
UIImage *photo = [UIImage imageWithData:img];