FTP = File Transfer Protocol
HTTP = HyperText Transfer Protocol

So, I don't know what you mean by "using hosting company", but I'm guessing you mean some control panel that hosting company provides, where you can also upload files?

FTP, like name already says, is made for file transferring. FTP cannot display images, even text directly. It is made purely for file transfer.
HTTP is protocol you use every day to browse the web, as HTTP can display images, text.. complete websites.

There is no such thing as "FTP site", there is just a directory with no index file that HTTP can automatically find and display. Usually you can view directory with both protocols if they are not password protected.


Now, to upload files I would definitely recommend using FTP, you can upload unlimited files at once, also FTP is usually a bit faster. But if you want to upload one file which is few mb's or smaller there's no difference really. But many times you need to upload 30-40 directories/files, then I would definitely use FTP.