FileImage reduceImageBitDepth(FileImage src, unsigned char bits) {
	FileImage result = allocateFileImage(src.width, src.height);

	unsigned char maximum8 = (unsigned char) (pow(2, 8) - 1);
	unsigned char maximumBits = (unsigned char) (pow(2, bits) - 1);
	unsigned char multiplier = maximum8 / maximumBits;

	if ((bits > 8) || (bits < 1)) {
		printf("Invalid bit depth %u", bits);
		exit(-1);
	}

	for (unsigned int y = 0; y < src.height; y++) {
		for (unsigned int x = 0; x < src.width; x++) {
			result.data[y][x] = (unsigned char) (round(((float) src.data[y][x] / maximum8) * maximumBits) * multiplier);
		}
	}

	// 8bit to 1bit
	//old gray level { src.data[0][0] = 240 }
	//maximum8 = 255
	//maximumBits = 2^1 - 1 = 1
	//multiplier = 255 / 1 = 255
	//new gray level { result.data[0][0] = (round(((float) 240 / 255) * 1) * 255) = 240 }

	return result;
}