EMS (Enhanced Messaging Service) is a direct descendant of SMS (Short Messaging Service). EMS extends text messaging to include small graphics, melodies, animations and long, formatted text messages. EMS is frequently used to send ringtones and wallpapers to phones from the web.
Nokia Picture Messaging is a similar but proprietary technology supported on Nokia and some Samsung phones. EMS is an industry standard.
EMS is older and less capable than MMS, which can handle true photos and larger multimedia files.