> from PIL import Image
> im = Image.open(r'D:\CSDN\Python_Programming.png')
> r,g,b,a = im.split()
> im = Image.merge("RGB",(r,g,b))
> im.save(r'D:\CSDN\Python_Programming.jpg')

> import cv2
> im = cv2.imread(r'D:\CSDN\Python_Programming.png')
> cv2.imwrite(r'D:\CSDN\Python_Programming.jpg', im)
True

> import cv2
> from PIL import Image
> import numpy as np
> im_pil = Image.open(r'D:\CSDN\Python_Programming.png')
> im_cv2 = np.array(im_pil)
> cv2.imwrite(r'D:\CSDN\Python_Programming.jpg', im_cv2)
True

> import cv2
> from PIL import Image
> im_cv2 = cv2.imread(r'D:\CSDN\Python_Programming.png')
> im_pil = Image.fromarray(im_cv2)
> im_pil.save(r'D:\CSDN\Python_Programming.jpg')

def PilImg2WxImg(pilImg):
  '''PIL的image转化为wxImage'''
  image = wx.EmptyImage(pilImg.size[0],pilImg.size[1])
  image.SetData(pilImg.convert("RGB").tostring())
  image.SetAlphaData(pilImg.convert("RGBA").tostring()[3::4])
  return image
def WxImg2PilImg(wxImg):
  '''wxImage转化为PIL的image'''
  pilImage = Image.new('RGB', (wxImg.GetWidth(), wxImg.GetHeight()))
  pilImage.fromstring(wxImg.GetData())
  if wxImg.HasAlpha():
    pilImage.convert( 'RGBA' )
    wxAlphaStr = wxImg.GetAlphaData()
    pilAlphaImage = Image.fromstring( 'L', (wxImg.GetWidth(), wxImg.GetHeight()), wxAlphaStr )
    pilImage.putalpha( pilAlphaImage )
  return pilImage

> from PIL import Image
> import numpy as np
> a = np.random.randint(0,256,((512,512,3)), dtype=np.uint8)
> im_pil = Image.fromarray(a)
> im_pil.save(r'D:\CSDN\random.jpg')