[tlug] Colormap of a PNG file

["Hung Nguyen Vu" <vuhung16plus+shape@example.com>]

Hi all,

I will a PNG file whose format is paletted color.

How can I find what RGB colors are using in this PNG file,
and how many colors are used in the color palette?

Will the colors of a PNG file will change if I use Graphics Magick
to convert it from PNG to GIF, like this:

"gm convert file.png file.gif"

# FYI, for gif files we can use the "convert" utility from Graphic Magick or Image Magick. 
# gm convert 3genMap.gif histogram:- | gm identify -depth 8 -format %c -

-- 
Best Regards,
Nguyen Hung Vu ( Nguyễn Vũ Hưng )
vuhung16plus{remove}@example.com , YIM: vuhung16 , Skype: vuhung16dg
Japan through an eye of a gaijin:
http://www.flickr.com/photos/vuhung/tags/fav/