It should be perhaps possible to create a .dwg CAD drawing from JPEG image of technical drawing. However, this would most likely require a software with some kind of tracing function (i.e. that converts bitmap shapes to vectors) and heavy manual editing by the user. The result of such jpeg to dwg conversion might not be great though, it will depend on the complexity and the quality of the original image.
Open JPEG file Open DWG fileA 3D CAD translation software
A CAD CGM converter