- (UIImage *)testChangeImageToBase64String
{
    UIImage *processedImage = [UIImage imageNamed:@"myFile.jpg"];

    // UIImage to unsigned char *
    CGImageRef imageRef = processedImage.CGImage;
    NSData *data = (NSData *) CFBridgingRelease(CGDataProviderCopyData(CGImageGetDataProvider(imageRef)));

    // encode data to Base64 NSString
    NSString *base64EncodedDataString = [data base64EncodedStringWithOptions:0];
    // create encoded std::string
    std::string encoded([base64EncodedDataString UTF8String]);


    // ***************************************************************************
    // This is where we call the server method and receive the bytes in a std::string
    std::string received = encoded;
    // ***************************************************************************


    // get Base64 encoded std::string into NSString
    NSString *base64EncodedCstring = [NSString stringWithCString:encoded.c_str() encoding:[NSString defaultCStringEncoding]];

    // NSData from the Base64 encoded std::string
    NSData *nsdataFromBase64String = [[NSData alloc]initWithBase64EncodedString:base64EncodedCstring options:0];

CGImageRef base64ImageRef = [newCGImageRefFromString:nsdataFromBase64String];

UIImage *imageFromImageRef = [UIImage imageWithCGImage: base64ImageRef];

return newImage;
}

UIImage *newImage = [[UIImage alloc] initWithData:nsdataFromBase64String];

// NOTE: have not tested if this even compiles -- consider it pseudocode.

CGImageRef image;
CFDataRef bridgedData;
CGDataProviderRef dataProvider;
CGColorSpaceRef colorSpace;
CGBitmapInfo infoFlags = kCGImageAlphaFirst; // ARGB

// Get a color space
colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
// Assuming the decoded data is only pixel data
bridgedData  = (__bridge CFDataRef)decodedData;
dataProvider = CGDataProviderCreateWithCFData(bridgedData);

// Given size_t width, height which you should already have somehow
image = CGImageCreate(
    width, height, /* bpc */ 8, /* bpp */ 32, /* pitch */ width * 4,
    colorSpace, infoFlags,
    dataProvider, /* decode array */ NULL, /* interpolate? */ TRUE,
    kCGRenderingIntentDefault /* adjust intent according to use */
  );

// Release things the image took ownership of.
CGDataProviderRelease(dataProvider);
CGColorSpaceRelease(colorSpace);