To post an image they need to be placed on a website such as flikr . The web address (right click on the photo and copy the address from properties) can be linked to a page here. The max size is i believe 800 pixels wide. To place the image here you press the icon seen in the message writing panel that looks in appearance like a letter albeit with a mountain and the 'stamp' is the sun!
An altnative is to place [img] before the web address and [/img. ] without the dot or space after your image address. Hope that helps. If it all goes wrong, pm me with the address of the photo and i will do the link for you.