H3 entry headlines show with different font sizes !!

This is with K2.
Some of my H3 entry headlines seem to ‘work’ as planned, right colour and correct font size.
Other entries have smaller fonts, as if they were not H3 anymore.

I’m implementing wp-imagerepacements, hoping it would fix my problem and look good… but I was wrong. wp-imagereplacement works where it should so it’s not related.

You can see on http://www.digitalfrog.nl (I’m a nightclub photographer so don’t click on this if you have kids around you)

Thanks for any ideas you may have, I will post any .css code you may need.

Cheers

Ralph