[PLUG] Strange Image Magick issue

[Felix Lee]

"Matt Alexander" <m at pdxlug.org>:
> When I use convert without any options, I get the following:
>   convert image.tiff image.png
>   117K image.tiff
>   206K image.png
> I'm not sure why PNG is so much larger, but whatever...
> Here's the odd part:
>   convert -resize 50% image.tiff image-50.png
>   654K image-50.png
> The image looks 50% smaller when I open it, but why did the file size
> balloon?  And what do I need to do to make it a smaller file size?

-resize usually increases the number of colors, because it tries
to make a 'faithful' representation of the original.  More colors
usually makes the file size larger.  You can choose the resize
algorithm with the -filter option.  You can reduce the number of
colors with the -colors option.

-sample just throws away pixels, which is easy and fast but
doesn't usually look as good.

A combination of -resize and -colors might get you better-looking
results than -sample, without being much larger in file size.
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