尝试不同的基本实施64，我用从一个讨论会的开源项目：

Try a different base 64 implementation, I use the one from colloquy open source project:

    #import "NSDataAdditions.h" 

    /* encoded string to image */
    NSString *imageString = @"";
    NSData * data = [NSData dataWithBase64EncodedString:imageString];
    UIImage *image1 = [UIImage imageWithData:data];

    /* image to encoded string, back to image */
    imageString = [UIImagePNGRepresentation(image) base64Encoding];
    data = [NSData dataWithBase64EncodedString:imageString];
    UIImage *image2 = [UIImage imageWithData:data];

获取 NSAdditions 文件：的 NSAdditions.h + NSAdditions。米