I notice that the icon in zenpage doesn't display properly on dark background. So i mage new emoticon with transparency.

You can grab this zip here :
http://www.neufgiga.com/n/50-17/share/LNK830349ecb5c3bd216/

The file format is in png, the original is in gif, so you have to change the emoticons.htm

The emoticons.htm goes in : \zp-core\plugins\tiny_mce\plugins\emotions
The icons files goes in : \zp-core\plugins\tiny_mce\plugins\emotions\img

Regards
Laurent

Note that you will need to make that change again with every update as these emoticons are part of a TinyMCE plugin.