Raster image files such as JPEG, TIFF and other supported formats, cannot be stored inside an AutoCAD drawing.
The current mechanism for associating raster image files with drawings works similarly to the way external references (xrefs) are associated to drawings.
The raster image can only be referenced in the drawing.
The actual data containing information on how to represent the raster image remains in the raster image file itself.
Therefore, the raster image file must accompany the drawing file when transported, or the raster data will not be represented when the drawing is opened.