upload a bunch of files with each own preview file and thumbnail

[Webcr0ler]

hi,
how can i upload some cbz files with covert and using that covert as thumbnail of the cbz.
i've a forlder with 3 or more cbz.
can a do that only with the command line or do i have to write a script for that ?
command : telegram-upload --to channel --thumbnail-file {file.stem}.jpg .
does upload the cover and the file but without the thumbnail.