For Barb and anyone else: After you click Go Advanced, you still do not use the icon. After the advanced screen opens, scroll down and you will see a button that says Manage Attachment. Click this button and another window will open, separate from your current window on your screen. At the top it will say search images and you click there, and select the pic you want from your computer. Once you do that, then you click upload just below the window. It will then show further down that the pic has been uploaded and how much of your allowed data you have used. You can continue to upload photos until you have used all the allowed data space.
When it shows the photo uploaded in the separate box, it is also added to your message at that time. After you send your message, you can then close the manage attachments window.
I hope this helps.