If the images of the PCBs are accompanied by schematics, you could rebuild the circuit using these and use the image of the existing circuit as reference for how to lay out the components on the PCB while routing all traces yourself (e.g. if the scans are not good enough to work with them directly).
You might be able to end up with nicer or more compact PCBs just because you can use smaller vias and traces or even inner layers today.
You might be able to end up with nicer or more compact PCBs just because you can use smaller vias and traces or even inner layers today.