Today, converting technology from JPG/PNG to Vector is so easy.
And if you want convert JPG to .prt or step file you need convert it to the vector first.
These is the steps :
1. You need at least 2 software. Inkscape and Engineering CAD software (autodesk inventor, autocad, solidworks or others). You can download inkscape here : https://inkscape.org/en/download/
2. Open Inkscape. And choose file that you want to convert.
3. After the image is open. Click the image. You must click the image. If not, you can't get the vector. After that, click PATH and then click TRACE BITMAP. Don't change anything if the resolution is high and the colour is black and white. If the resolution is low you need increase threshold of brightness cutoff.
4. On the right below, you can see UPDATE button. Click it. You can see the preview of the file. That is vector. Then, you can click OK Button.
5. Slide the image. You can see two different. The one is black and the other is not. Delete the colour one.
6. Click the black one, and Save As file. Choose SVG if you want edit with non engineering CAD software, and choose DXF if you want edit with engineering CAD software such as Autocad or Inventor.
7. It will appear option if you choose dxf. Click OK Button.
8. You can check the result with CAD Software. Insert the DXF and change it into solid. And it's Done. Hope it answer your question.