Ask for preview image that is not cropped

Hi,

I’m quite happy with the image preview system in Nextcloud. I get them with that kind of link in my app :

http://mynextcloud.org/index.php/core/preview.png?x=1200&y=900&forceIcon=0&file=%2Fmyimage.JPG

Is there any way i could ask Nextcloud core to generate the previews without cropping them ?