[Image-SIG] [image-sig] controlling brightness of the image

[Fredrik Lundh]

Fredrik Lundh wrote:

>      "Quality values above about 95 are NOT recommended for
>      normal use; the compressed file size goes up dramatically
>      for hardly any gain in output image quality."

to illustrate, here are the output sizes for the standard "LENNA" image, 
for some quality settings/formats:

  50 22833
  60 26253
  75 35292 (default)
  80 41162
  85 49294
  90 64280
  95 99870
100 219203
PNG 491272
RAW 786432 (uncompressed, w/o header)

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