PNG filesize

Hi all,

I'm trying to find ways to make the file-size of my PNG images smaller.

When I generate my 660*440px image I get a big 168kb file.
(8bit RGB color model, has an alpha channel (need that) but no
interlacing scheme)

Here it is:
http://metphys.org/eme/T05.png

I'm using the savefig method of-course.

To see how much I could compress it I used pngcrush (the best tool
according to the interwebs) and got it down to 128kb.

But thats still way to large for my intended use. (plotting results
from an operational weather model, see. www.belgingur.is
We are currently using IDL.)

From what I've read about PNG files, which is supposed to be rather
compact image format, it seems to me that the most effective way is
to have an indexed color table.

So to cut it short:

Is there any way to save a PNG file with an indexed color table?

Or do you see any other way to shrink the files?

Best regards.
Einar M. Einarsson
www.belgingur.is

Jpeg.

ยทยทยท

On Mar 25, 2008, at 8:12 AM, Einar M. Einarsson wrote:

Hi all,

I'm trying to find ways to make the file-size of my PNG images smaller.

When I generate my 660*440px image I get a big 168kb file.
(8bit RGB color model, has an alpha channel (need that) but no
interlacing scheme)

Here it is:
http://metphys.org/eme/T05.png

I'm using the savefig method of-course.

To see how much I could compress it I used pngcrush (the best tool
according to the interwebs) and got it down to 128kb.

But thats still way to large for my intended use. (plotting results
from an operational weather model, see. www.belgingur.is
We are currently using IDL.)

From what I've read about PNG files, which is supposed to be rather
compact image format, it seems to me that the most effective way is
to have an indexed color table.

So to cut it short:

Is there any way to save a PNG file with an indexed color table?

Or do you see any other way to shrink the files?

Best regards.
Einar M. Einarsson
www.belgingur.is

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