Yes, you can attach a picture to any message if you select to send it as an MMS message on your Send a Message page.
Each MMS message counts as 3 messages sent per recipient.
If using the mobile app
If using the mobile app, you can click the paper clip icon on the Send Message screen and the following will pop up:
Selecting "Image" will allow you to select an image from your library or take a photo to attach to your message. This converts your message into an MMS, which also increases your maximum character count to 1550 instead of 160. (Note that each MMS counts as 3 messages per recipient instead of 1, and MMS will be sent to your subscribers through a different number than regular messages.)
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