[magick-users] merged multiple jpeg files into multipage tiff: size grows, why?

[Anthony Thyssen]

Zhang Weiwu on  wrote...
| Dear list:
| 
| This is my first time try convert(1). I did this:
| $ convert 1329.jpg 1330.jpg -adjoin identity.tiff
| 
| The two images are here:
| gopher://sdf.lonestar.org/I/users/weiwu/1329.jpg
| gopher://sdf.lonestar.org/I/users/weiwu/1330.jpg
| 
| Both images are less then 300KB in size, however the converted tiff
| image is as big as 1331KB. This is strange as tiff file is twice as big
| as it should be. As compression method shouldn't been changed (still
| JPEG inside the TIFF) I wonder how this comes to be and, is there a way
| to generate tiff image less then 600KB? Thanks in advance!
| 
| I also tested the generated tiff image to make sure it's still in JPEG
| compression:
| 
Did you try adjusting the -quality setting for the JPEG's?

Does that make a difference?

Also reading and re-saving JPEG files (with JPEG lossy compression)
is NOT a good idea.  Doing so degrades the image.  That is the price you
pay for using a higly compressed JPEG image.

I do know know of a lossless insert of JPEG to TIFF images.
If there was it would proably make a good IM delegate (external
converter program).


  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
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