thanks that works.

not really
you can get the preview from a BaseDocument with GetDocPreviewBitmap();
but this works only with loaded files, and i don't want to load all files first.

I saw you can browse a folder of files and get the file informations here:
https://developers.maxon.net/docs/cpp/2023_2/page_manual_browsefiles.html

Is it also possible to get the preview images from those files? And how?