python script to identify those fault jpg images in a directory.

remove_wrong_jpeg.py

import glob 
import os 
import re 
import logging 
import traceback

filelist=glob.glob("/path/to/*.jpg")
for file_obj in filelist:
  try:

        jpg_str=os.popen("file \""+str(file_obj)+"\"").read()
        if (re.search('PNG image data', jpg_str, re.IGNORECASE)) or (re.search('Png patch', jpg_str, re.IGNORECASE)):
            print("Deleting jpg as it contains png encoding - "+str(file_obj))
            os.system("rm \""+str(file_obj)+"\"")
  except Exception as e:
    logging.error(traceback.format_exc())
print("Cleaning jps done")

It deletes all PNG images that are stored with .jpg extension.
Most specialized image viewers can handle this and show the image but in other uses it causes troubles.