WoocCmmerce child problem

I installed the Nirvana child for WooCommerce and everything works like a charm – except one thing. Pictures now seem to be locked at a specific proportion (standing). This prevents me from adidng pictures (horizontal) to my new articels and blogposts. The are all locked in a proportion, no matter what size i choose or article template (blogpost, two colums ect) i choose.

How can I fix this?

Best regards

Mikael