quote Mumbles:
You’ll have to use another online image hosting site or your computer to supply photos for posting here. From your computer, click the ‘attachments’ button at the bottom of your draft. Then the ‘Add Files’ button will appear and you are all set. Just make sure you click the ‘Full Editor And Preview’ button first though for the other buttons to appear.
Do as said above, but do it the easy way–With two Windows open, drag and drop the picture from wherever you have it stored on your computer directly to the message box you are typing into. Then scroll down and click on "Place Inline". It will go to wherever your cursor is at the time. No photo hosting site required.