Getting image preview with android library or via WebDAV

Hello together,
I’m currently experimenting with the android-library (com.github.nextcloud:android-library) and download of images. I want to show a preview of some pictures, but don’t want to download the whole large image for that. Is it possible to get the generated previews or thumbnails from nextcloud or request images in a specific size?
I’m currently working with the android-library but would be interested in a WebDAV based solution too.

thank you

cc @tobiasKaminsky

For thumbnails (square):

For resized images (correct side ratio):

Is this API documented somewhere?