Thanks Jenny, unfortunately it doesn't seem to resume in my case after the internet connexion fails.
The file is 1GB, which is not THAT big, but it's big when you have internet problems
I'm interested in the option to assemble the already uploaded parts !
If the current upload fails again, I'll try this !
For now, it's 28% of the single file that is uploaded, so I prefer to wait quietely without disturbing my PC and the connexion ^^