Unifies graphical smilies (smileys) on page to defined appearance: half-transparent 4×4px square (mouse over it to reveal its hidden -beauty- _ugliness_).

Notes
- relies on keyword "like 'smilies'" in source URL or properly filled 'alt' attribute, nothing more -- not even a size -- so it is possible that it will match more than just smilies
- selectors set is just rough, for now (I hope it will be possible to tune it up to really working one)
- for a pity, FF2 cannot add a generated content after image elements, so adding a textual img[alt]:after { content: attr(alt) } does not work : (
- if you want it this way, you can use this userscript instead:
http://diveintogreasemonkey.org/casestudy/frownies.html
(contains pretty complex set of selectors, may serve here in future :] )
- Appearance of the hovered image in the 'After' screenshot is affected by http://freestyler.ws/style/3907/show-transparency-of-in-page-images-on-hover
- testing ground:
http://eldar.cz/myf/lab/desmileyfize/smiley_hell.html

changelog:
2008-09-05 - some new tweaks, see source
2015-03-31 - background-image smileys with title shown as plain text