Alignment / Gallery pictures

Can someone help me with this? It’s quite urgent, so would be really grateful for some help!

I have a new problem (everything used to work fine, now I wanted to add a few more pix and things are different > is it possible that settings have changed with recent updates?):

The two pictures on the top are aligned to the left, the ones underneath in the middle, but they are all set up as alignment “none” – how to fix that? I want them all centered, but choosing “center” doesn’t help

http://www.nicolekuderer.com/?cat=30