Writing images using dxflib

How to write image (e.g. bmp) into dxf file using dxflib?
Can someone provide me a minimal example?

I don’t understand the interface:
int writeImage(DL_WriterA& dw, const DL_ImageData& data, const DL_Attributes& attrib);
void writeImageDef(DL_WriterA& dw, int handle, const DL_ImageData& data);

Why do both methods contain DL_ImageData?

Thanks in advance.

Please refer to the QCAD DXF exporter code for an example of how to use this interface: