WhatsApp Media Messages
WhatsApp divides outgoing messages into two categories: template messages and session messages. Template messages are the initial messages you send to users and must follow a pre-approved template cleared by WhatsApp. Once a user starts a “session” by sending you a message, you can exchange free-form messages with them for 24 hours.
You can send media messages to any WhatsApp user who has sent you a message within the past 24 hours. If a user has not sent a message to your WhatsApp number within the past 24 hours, you cannot send them a media message through WhatsApp.
This is because WhatsApp only allows sending media on session messages.
WhatsApp supports sending and receiving images, audio, and PDF files. The following formats are currently supported:
|JPG, JPEG, PNG
|MP3, OGG, AMR
|MP4 (with H.264 video codec and AAC audio)
You can send media messages up to 16 MB in size. A WhatsApp media message can only contain one media object. Additional MediaUrl parameters will be ignored.
Adding a media attachment to a message does not affect the message price. Media messages have the same pricing as a standard Session message to the same destination country.