PRO SAVEIMAGE, FILE, $
  BMP=BMP, PNG=PNG, GIF=GIF, JPEG=JPEG, TIFF=TIFF, $
  QUALITY=QUALITY, DITHER=DITHER, CUBE=CUBE, QUIET=QUIET

;- Check arguments
if (n_params() ne 1) then $
  message, 'Usage: SAVEIMAGE, FILE'
if (n_elements(file) eq 0) then $
  message, 'Argument FILE is undefined'
if (n_elements(quality) eq 0) then quality = 75

;- Get output file type
output = 'JPEG'
if keyword_set(bmp)  then output = 'BMP'
if keyword_set(png)  then output = 'PNG'
if keyword_set(gif)  then output = 'GIF'
if keyword_set(jpeg) then output = 'JPEG'
if keyword_set(tiff) then output = 'TIFF'

;- Check if GIF output is available
version = float(!version.release)
if (version ge 5.4) and (output eq 'GIF') then $
  message, 'GIF output is not available'

;- Get contents of graphics window,
;- and color table if needed
image = screenread(depth=depth)

if (depth le 8) then tvlct, r, g, b, /get

;- Write 8-bit output file
if (output eq 'BMP') or $
   (output eq 'PNG') or $
   (output eq 'GIF') then begin

  ;- If image depth is 24-bit, convert to 8-bit
  if (depth gt 8) then begin
    case keyword_set(cube) of
      0 : image = color_quan(image, 1, r, g, b, $
            colors=256, dither=keyword_set(dither))
      1 : image = color_quan(image, 1, r, g, b, cube=6)
    endcase
  endif

  ;- Reverse PNG image order if required
  if (output eq 'PNG') and (version le 5.3) then $
    image = reverse(temporary(image), 2)

  ;- Save the image
  case output of
    'BMP'  : write_bmp, file, image, r, g, b
    'PNG'  : write_png, file, image, r, g, b
    'GIF'  : write_gif, file, image, r, g, b
  endcase

endif

;- Write 24-bit output file
if (output eq 'JPEG') or $
   (output eq 'TIFF') then begin

  ;- Convert 8-bit image to 24-bit
  if (depth le 8) then begin
    info = size(image)
    nx = info[1]
    ny = info[2]
    true = bytarr(3, nx, ny)
    true[0, *, *] = r[image]
    true[1, *, *] = g[image]
    true[2, *, *] = b[image]
    image = temporary(true)
  endif

  ;- Reverse TIFF image order
  if (output eq 'TIFF') then $
    image = reverse(temporary(image), 3)

  ;- Write the image
  case output of
    'JPEG' : write_jpeg, file, image, $
               true=1, quality=quality
    'TIFF' : write_tiff, file, image, 1
  endcase

endif

;- Report to user
if (keyword_set(quiet) eq 0) then $
  print, file, output, $
    format='("Created ",a," in ",a," format")'

END