A JPG is a grid of coloured pixels. A DXF (Drawing Exchange Format, the open CAD format Autodesk introduced with AutoCAD) is a list of geometry: lines, arcs and polylines with coordinates. A JPG to DXF converter therefore has to find the edges of every shape in the picture and redraw them as vector outlines. Changing the file extension or wrapping the pixels in a DXF does not work: CAD and CAM programs need paths they can select, offset and cut.
Many free JPG to DXF converters take exactly that shortcut, or trace with a single brightness threshold, and you get jagged stair-step edges, hundreds of fragments, or a raster image stuck inside the drawing. We trace with the same AI vectorizer used for logos and print files, which fits smooth curves and straight lines to the shapes, then write each shape to the DXF as a closed polyline in millimetres.
The result is a 2D drawing you can scale, dimension and cut. It is not a 3D model and it does not recognise text as editable CAD text: letters become outlines, which is what a laser or plotter needs anyway.