If you are sending an MMS message, you don't know.
You don't know anyting about the device that is connecting.
The content adaptation and conversion functions in the Now SMS/MMS Gateway's MMSC will detect the device when the recipient device connects to retrieve the message. And it will consult the User-Agent Profile for the device to determine device characteristics. For monochrome devices, the content adaptation services convert GIF/JPEG/PNG images to WBMP monochrome format.