You can just include the imageurl ( i.e. http://www.somedomain.com/Images/cool.gif) in your message. Or you can also upload an image(this option has to be enabled by the administrator) by clicking on Click here to choose your file on the post form. This will launch a remote window through which you can specify the file extension and browse your disk to select the file you wish to upload. Once the file is selected, the attachment textbox will automatically be populated with the name of your uploaded file. All files are randonmly renamed. Keep in mind that there is a size limitation to file upload.