Folder that automatically uploads to phone
FolderSync could come in handy here. Define a "folder pair" (i.e. which directory on your Android device to sync with which directory on your computer), using any of the available protocols (SFTP, Samba, or any other). Then either chose for some "auto-check" (e.g. have it synced every night), or push the button manually. Using the paid version, you could even bring in tasker – which is what I do: "Every night at 3am, when connected to any power source and to MY_WIFI network → Sync all my backups, photos, whatsnots" :)