Picture of Posts not Scaling

Hello,

I have the problem that squeezed the images of a post look.
I’ve the picture size from 802*636px taken, but in the front Display it’s squeezed, and in the Post is the Picture on the Top not the middle

Link: http://bestru.sirius.uberspace.de/LittleWhoop_wp/guardians-of-warcraft/
Screenshots:
Squeezed Image:
http://epvpimg.com/jU9yc
Incorrect Scaling or wrong position:
http://epvpimg.com/pwZEe
Original Picture:
http://epvpimg.com/bgq1c