pythonを利用して実現します。dcmフォーマットの画像は.jpgフォーマットに変わります。

import pydicom 
import matplotlib.pyplot as plt 
import scipy.misc 
import pandas as pd
import numpy as np
import os 


def Dcm2jpg(file_path):
  #        
  c = []
  names = os.listdir(file_path) #  
  #               .dcm  
  for name in names:
    index = name.rfind('.')
    name = name[:index]
    c.append(name)
 
  for files in c :
    picture_path = "/home/dell/Desktop/Dcm/"+files+".dcm"
    out_path = "/home/dell/Desktop/Dcm1/"+files+".jpg" 
    ds = pydicom.read_file(picture_path)
    img = ds.pixel_array #        
    scipy.misc.imsave(out_path,img) 
  
  print('all is changed')
      
Dcm2jpg('/home/dell/Desktop/Dcm')

#import scipy.misc 
import os 
from PIL import Image
def bmp2jpg(file_path,out_path): 
#         
  c = [] 
  names = os.listdir(file_path) #   #               .bmp   
  for name in names: 
    index = name.rfind('.') 
    name = name[:index] 
    c.append(name) 
  for files in c : 
    picture_path = "/home/dell/Desktop/unet/d/Mask/"+files+".bmp" 
    out_path = "/home/dell/Desktop/unet/d/Mask1/"+files+"_mask.gif" 
    im = Image.open(picture_path)
    im.save(out_path)#scipy.misc.imsave(out_path,im) 
  print('all is changed') 
bmp2jpg('/home/dell/Desktop/unet/d/Mask','/home/dell/Desktop/unet/d/Mask1')