On Wed, Apr 05, 2000 at 06:21:33AM +0200, Marc Lehmann wrote:
> On Mon, Apr 03, 2000 at 05:24:37PM +0200, Stanislav Brabec <[EMAIL PROTECTED]>
>wrote:
> > Saving in higher quality means vaste of disk space. Saving with less quality
> > will cause loss of quality. So the best is to save certain jpeg in the same
> > quality all times.
>
> You got it wrong: saving a jpeg in ANY quality (higher or lower) causes loss
> of quality. Saving in the same quality as the original image causes quality
> loss depending on the selected quality.
>
> As I said, the only effect is a similar(!) file size, and that every save
> would cause about the same amount of quality loss.
Yes, similar file size and similar(?) quality is the goal of saving
jpeg in the same quality every time.
>From my experiences, loading a 25% q jpeg and saving it as 75% will
cause significant raise of file size (and no gain of quality ;-).
(I cannot repeat this experiment with actual CVS version -
jpeg plugin crashes while changing quality!!!)
Back to original problem:
If GIMP cannot guess some plugin-specific value (e. g. quality for jpeg) from
loaded data, let it opens "xxx save options" dialog, even if it is invocated as
"Save". It's good and clear solution.
Particularly, for jpeg one can save some options to image comment or
to some APP marker.
--
Stanislav Brabec
