If you need to modify only one dimension of an image, use only one of the method arguments. In that case, the value of the skipped argument is automatically adjusted to maintain the ratio of the image.
When I am using only the height property the image does not retain the ratio. The width is kept as is. So in my case it is a stretch. Is it a bug or a feature? 
Hi @Jorg_Beyer,
thanks for reporting this!
It looks like we have a bug, but I’m sure we can fix it very soon.
I’ve created a task (BKNDLSS-30030) for our engineer, we will inform you as soon as we release a new version of the service with a fix.
Regards,
Stanislaw
Hello @Jorg_Beyer
We have fixed this problem in the service. As I wrote in the other thread - you need to reinstall the service. Please let me know if the fix works for you.
Regards,
Inna