Replace positional argument with data

Question

I am working on project which uses potrace which convert format .bmp to .svg and the its terminal code is

potrace <input bmp file path> --svg -o <output svg filename>

The input .bmp images are generated from .png images using other algorithm. I have to convert 1000s of these bmp files to svg. After conversion to svg these images will be converted back to png files (This will help me upscale the black and white images) Now my problem is that I have to save .bmp images as a file on disk and then run above command to convert to svg which I believe is time consuming (i.e. saving file to disk insted of inmemory).

Is there any way or method which can help me reduce this time like modifying the command or saving image as temporary file or something else.

Here is my complete code

from PIL import Image
import numpy as np
import os
import cv2
import matplotlib.pyplot as plt
import time
import io

image = cv2.imread('0000.png')
img_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
ret, thresh = cv2.threshold(img_gray, 150, 255, cv2.THRESH_BINARY)
thresh=thresh
con = cv2.imencode('.png', thresh)[1].tobytes() # Earlier I was using imwrite which takes more time

img1 = Image.open(io.BytesIO(con))
file_out = "000_2.bmp"
img1.save(file_out)

os.system('potrace 000_2.bmp --svg -o 000_3.svg')

# some code to convert svg to png