To add an image to a message you need to make sure you have the photo link from the photo section of MemberHub.
To do this:
1. Upload the image in the image section. Go to: Admin Console > Hubs > Select the Hub you want to message from > Photos > Click Add Files
2. Next, copy the link for the image by clicking the image and clicking copy link.
3. Last, insert this link into the message. Click messages > new message > insert > Insert/Edit Image.
4. Once you click Insert Image, fill in the pop-up. Insert the link in the source box. The Image Description and Dimensions are not necessary.
5. Hooray! Your Done. This is what it will look like in the message. You can resize the image if needed by dragging the corners of the photo. From here, you can finish your message as necessary by adding additional text, recipients etc.