Images are an important part of Messages you send and Whiteboards that you create. In order to add images in these two features, you need to follow these steps:
1. To insert an image into a message or whiteboard, the image has to be hosted somewhere. An easy way to make sure that it is hosted is that you can add it in as an image to MemberHub under Files or Photos section. Once it's loaded there you can use the "Copy Link" feature to get the full path the image.
You could create a photo album just for images to use in your messages. Then when you click on a photo you'll get the popup and you can use the Copy Link to grab the URL to the image.
Also, see the Copy Link in the Files section after you've uploaded an image:
2. In the New Message page, on the format bar, go to "Insert"->"image"
3. Insert the source url for the image and any additional description
Note: any image that is saved on your computer will NOT work since it is not hosted anywhere on the web.
In the "source" box, input the image url. Simply paste the url that copied from the Files or Photos section into the source box. You do not really need to fill out the rest of the info fields. By default, the dimensions on the image will be the ones from where you copied from. The "constrain proportions" check box will also be checked by default.
4. Click "OK" and the image will now be displayed in the text box. You can format it to the proportions of your choosing.