MMS media messaging
When sending text and pictures in the same message (MMS messaging), a message can contain up to 10 images and 1600 characters, as long as the entire message is under 5 MB in size. 1600 characters will take up 4.8 KB, which accounts for roughly 1% of the message size limit.
Twilio will automatically compress JPEG, PNG, or GIF files to reduce their size if they exceed certain thresholds, to help you fit more images on your message when needed. For details about media support, see Twilio Programmable SMS Supported File Types and Size Limits for MMS Media Messages.
WhatsApp media messaging
The 5 MB total message size limitation described above does not apply to WhatsApp media messaging on Twilio. WhatsApp media message behavior and limits are described in Sending and Receiving Media with WhatsApp Messaging on Twilio.