[Mediawiki-l] TeX-rendered formulae look "ugly"

Hello,

I've managed to setup TeX with my local wiki (MediaWiki 1.2.3). At first, it worked (almost) fine, but some formulae couldn't be rendered, some could. I tried to "fix" this by using newer versions of tetex & co, but this didn't solve the problem. But now I have another problem: The generated TeX-PNGs look ugly, compared to those that were created before I changed to the new versions. Examples (generated from <math>1234{,}56</math>):

From my wiki:

http://sveith.dyndns.org/8cwiki/upload/math/ec13bd79cd7914f84ee4eee6299b7c27 .png

From Wikipedia:

http://de.wikipedia.org/math/ec13bd79cd7914f84ee4eee6299b7c27.png

Switching back to the old version of tetex didn't help; it must be some setting deep in some configuration file. Has anyone got a clue?

Thanks in advance Simon Veith