optimising image size

[daz4126]

Hi,

I've created an icon theme using inkscape to make svg icons that are then exported to make 48x48 pngs.

I then resize these using the Nautilus resize image extension. But this seems to leave me with huge images. If I reduce the size using Gimp then the files are much smaller.

Is there any way that I can quickly reduce the size of a load of icons in one go and also a way of optimising the image size - my icon theme is much larger in size than the Human icon theme, yet it has less files!

thank,

DAZ

[Pro-reason]

So you're talking about reducing file size after an operating to reduce image dimensions results in a large file?

There are several tools to optimise PNGs.

Install them all!


sudo apt-get install pngcrush optipng advancecomp


An even better tool is pngout (http://www.jonof.id.au/index.php?p=kenutils), but it cannot be added to the Ubuntu repositories, because it is not open-source.

[Pro-reason]

Once you have installed one or more image optimisers, run any one of them thus:

(assuming that you are in a directory that contains PNGs)



# This is from the advancecomp package.
# It will optimise files in-place.
advpng -z4 *png


# pngcrush can only optimise in place if we do one file at a time.
# So, we make an output directory.
mkdir output && pngcrush -d output *png


# optipng will optimise files in-place
optipng -o7 *png


# pngout can only handle one file at a time.
# So, we have to cheat, with a “while” loop.
ls -1 *.png | while read IMAGE; do pngout $IMAGE; done