Hover issues

Hi

I got some problems with the hover effect. It’s always smaller than the hover effect. I always tried to solve it with Regernerate Thumbnails but it won’t work. And i oon’t use some other plugins.

My photos are always shrunk as soon as I set them as a post picture. Hope u can help me.

Thx!

The page I need help with: [log in to see the link]