cropping a random part of an image

[drewes.mil at gmail.com]

Hi Peter, Hi Robin, 

thanks for your help, and especially for the code ;)

@Peter: thanks for the links, I know, it is always better to write the code than to copy and paste!

@Robin: the question, iḿ trying to answer is, if good pictures, in this case portraits, also have good "Parts", so if the beauty of a picture can be found in its crops, too.
In the and it is for a deep CNN and I hope it will work!

Thanks again!

Steffen