Objective-C从远程地址下载图片

- (UIImage *) getImageFromURL: (NSString *)theURL {
    UIImage *theImage = NULL;
    NSString *imageFileName = [BT_strings getFileNameFromURL:theURL];
    NSData *imageData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:theURL]];
    theImage =  [[UIImage alloc] initWithData:imageData];
    [BT_fileManager saveImageToFile:theImage fileName:imageFileName];
    return theImage;
}