import vapoursynth as vs
core = vs.get_core()
ret = core.imwri.Read("image.png")
ret = core.nnedi3.nnedi3_rpow2(ret, 2) # 2 being the scaling factor - could also be 4, 8, 16, etc
ret = core.imwri.Write(ret, "PNG", "image.2x.%d.png")
ret.set_output()