curl --upload-file file.jpg https://www.hostfil.es
curl -Ffile=@file.jpg https://www.hostfil.es
curl -Ffile[]=@file1.jpg -Ffile[]=@file2.jpg https://www.hostfil.es
Or anything else that will send it as either a PUT or POST body.
Note that if you want to send multiple files the field needs to be named file[] and you need to use multipart/form-data.
If you don't use multipart/form-data then the whole request body must be the single file you wish to upload.