Got that. I used the code and adjusted the featured-image width to 150px and the max width to 70%, because there is more room.
You can see the result on remech.koeln as usual, but there is a small problem with blog post headers which have more than one row (scroll down and you will see what i mean).
This is because i made the featured image smaller, but I thought you might know a way to place these headers a bit higher, depending on how many rows or characters they have.
I doubt thats possible though ^^
Thanks for everything, you were a great help to me.