function komp,img1,img2,limit=limit


 img1 = readfits('/net/lasco6/data/fits/level_05/960327/c1/13003623.fts',h1)
 expt = SXPAR(h1,'EXPTIME')

 img1 = (img1 - 322)/expt
 img1 = REBIN(img1,1024,512) 

 img2 = readfits('/net/lasco6/data/fits/level_05/960327/c1/13003622.fts',h2)
 expt = SXPAR(h2,'EXPTIME')
 img2 = (img2 - 322)/expt

 IF NOT KEYWORD_SET(limit) THEN limit = max(img1)

  ;img1 is 1024x512
  tmp1 = img2
  tmp1 = img1(257:257+511,*)

  mask = where(tmp1 GE limit)
  IF mask(0) EQ -1 THEN mask(0) = 0

  tmp1(mask) = img2(mask) 
  img1(257:257+511,*) = tmp1
  image=img1
  
  tvscl,image<limit

RETURN,image
END