...or any other section for that matter.
Create your message just as you might for one which contains only text. Don''t click 'submit' just yet.
Then, click on the 'upload attachment' tab below the text entry box..
Click the 'browse' button to find the file you wish to upload, then click the 'add the file' button...
Then click the 'submit' button and Voila!
You may choose to have the image displayed in the middle of your text by clicking the 'place inline' button, or the image(s) will simply be added to the end of your message.
You can edit the post and delete/change the image at any time.