Smart Messaging
Smart messaging is a proprietary service developed by Nokia used for the sending and receiving of various digital media via SMS.
Graphical
Picture message
A monchrome picture that can be sent between handsets as a series of SMS messages. The typical size of a picture message is 72x28 pixels, which is sent as three separate SMS messages. Most Monochrome Nokia handsets allow the picture message to act as a screensaver. Most colour ones do not.
The picture message uses an implementation of the OTA bitmap.
Operator logo
A monchrome picture that can be sent to a handset via an SMS gateway as either a single or a series of concatenated SMS messages. The typical size of an Operator Logo is 72x14 pixels, which is sent as two separate SMS messages.
Operator Logos sit in the middle of the screen and disappear when coverage is lost. The original intent of Operator Logos was to allow a Network Operator or MVNO to replace the name of their network (as stored on the SIM card with their graphical logo, but human nature being what it is, people now usually get one that represents them rather than their network.