os.walk(Path("path_string")) giving error

[snippsat]

TypeError: scandir: illegal type for path parameter

You get this error because you use Python 3.5.
Have to use Python 3.6 or newer for os.walk() to take pathlib object.
You use can it directly like this os.walk(dir_to_scan).
You should of course install a new version Python 3.8 (3.6-3.7) and pip installation under Windows

Then you can also drop the old string formatting %s' % dirName and use f-string.

from pathlib import Path
import os

dir_to_scan = r"C:\code\img"
p = Path(dir_to_scan)
for root, dirs, files in os.walk(p):
    for fname in files:
        if fname.endswith(('.jpg', '.png')):
            print(f'Image found --> {fname}')

Output:
Image found --> nrk.png
Image found --> test.jpg