template <typename T>
class Image : public Eigen::Matrix <T, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>

Image<RGB<unisgned char>> or Image<RGBA<float>>

Image<unisgned char> image = ReadImage(const char* const filename);

Image<unisgned char> image;
bool b = ReadImage(const char* const filename, Image<unisgned char>& image)

class BaseImage
{
public:
    inline BaseImage() {};
    virtual inline ~BaseImage() {};

    virtual inline int Width() const = 0;
    virtual inline int Height() const = 0;
    virtual inline int Depth() const = 0;
    etc...
};

template <typename T>
class Image : public BaseImage, public Eigen::Matrix <T, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>

class ImageFactory
{
  typename <T>
  static BaseImage* createImage(const T* const src, const int& width, const int& height, const int& depth)
  {
    if (depth == 1)
    {
      return new Image<T>();
    }
    else if (depth == 3)
    {
      return new Image<RGB<T>>();
    }
    etc...
  }
}

class Image2
{
public:
    Image2(const char* const path)
    {
        // where ReadImage and external function that will call ImageFactory
        pBaseImage = ReadImage(path);
    }
    ~Image2();

private:
    BaseImage* pBaseImage;
};