网络获取图片高度和宽度

       [[SDWebImageDownloader sharedDownloader]downloadImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@!375x235",ImageRequest,model.titlepic]] options:SDWebImageDownloaderUseNSURLCache progress:^(NSInteger receivedSize, NSInteger expectedSize) {    } completed:^(UIImage *image, NSData *data, NSError *error, BOOL finished) {        //这边就能拿到图片了        NSLog(@"imgh = %f,%f",image.size.height,image.size.width);    }];