Yes, obviously you would have to upload at some point to get them into the cloud, but I was thinking the files could be manipulated locally first then the files + a script could be uploaded and processed remotely.
There definitely would be some cost to processing in the cloud, but I think it would be worth it.
I just look at apps like Adobe Photoshop CC that can be run on a Chromebook and I'm wondering why it's not being adopted more widely.