Autocad used to have the ability to import a bitmap image which you could then draw around, then output as dxf.
The one I used was Autocad light but that was some years ago so not sure if it still has the ability!!

Image2cad is a paid for package Img2CAD converts jpg to dxf,jpg to dwg,bmp to dxf,jpeg to dxf,jpeg to dwg,tiff to dwg,tif to dwg that works well!

Peter