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result png file size after montage compared to gimp
Posted: 2007-11-29T11:27:27-07:00
by dafi
I use montage to produce one finale png with four images.
All works fine but the final file size is ever bigger that the same saved with gimp.
How can I have size more similar to gimp?
Actually my images are RGB with Alpha channel, the command line I use is shown below:
Code: Select all
montage -strip -quality 100 \
-background none \
-geometry +0+0 \
image_1.png image_2.png image_3.png image_4.png \
result.png
Re: result png file size after montage compared to gimp
Posted: 2007-12-02T22:32:43-07:00
by anthony
PNG will store images with a lot of detail. So of course the result is bigger.
You can try using a different -quality setting for PNG (
see IM examples PNG, quaility)
or better still try using "OptiPNG" to compress you image better.
If exact color and no transparency is involve you can try saving to PNG8:image.png to get a color reduced version. Or you can use another PNG tool "pngnq" to do the same thing in a non-IM way, but attempts to preserve semi-transparency (which the IM PNG8 coder can not do.
Re: result png file size after montage compared to gimp
Posted: 2007-12-03T11:50:02-07:00
by dafi
Thank you for your hints, OptiPNG produces file size smaller than ImageMagicK and very closer to GIMP.
I love ImageMagicK and appreciate very much if it can have same OptionPNG capabilities.
Re: result png file size after montage compared to gimp
Posted: 2007-12-03T20:04:09-07:00
by anthony
That would be nice. and you can actually set up a 'optpng:' output delegate to get IM to call that program itself. (That would actually be a nice delegate example too if someone would care to figure it out.)
however the coders within IM are limited by the fact that IM is itself a general image processor. while optipng is a specialized processor so can spend more time and effort on just one part.
Re: result png file size after montage compared to gimp
Posted: 2007-12-03T20:24:26-07:00
by magick
Try this:
- convert logo: logo.pnm
convert logo.pnm png8:logo.png
ls -l logo.png
-rw------- 1 cristy cristy 36917 2007-12-03 22:19 logo.png
optipng -o7 logo.pnm
ls -l logo.png
-rw------- 1 cristy cristy 35384 2007-12-03 22:22 logo.png
The resulting images are fairly close in size.
Re: result png file size after montage compared to gimp
Posted: 2007-12-04T10:01:23-07:00
by dafi
magick wrote:
optipng -o7 logo.pnm
ls -l logo.png
-rw------- 1 cristy cristy 35384 2007-12-03 22:22 logo.png[/list]
The resulting images are fairly close in size.
This is what I want, my images after "-o7" cure are 38% smaller
Thank you