One of the fastest ways to transfer files between remote machines is using SSH:
tar -cz *.jpg | ssh <username@host> "tar -xzC <path-to-expand>"
This will create a single compressed archive of all jpg files in the current directory, transfer them securely to the specified host (logging in with the specified username), and then expand the archive and save the files to the specified path. Cool, isn’t it?
From my experiments this is faster than using scp, sftp and rsync. Note, though, that if you make further changes in your local directory after the initial copying to the remote machine, and you wish to sync those changes to the remote directory, then it is faster to use rsync. But the initial copying is faster using SSH.