As far as I know you can only post pictures that are already hoasted online.
1. Click the "reply" button on the bottom, left of this post.
2. Look across the top of the message text box and there will be two rows, the first of which will have the "fonts" and "sizes" among other options.
3. The second row, however, has a small image of what appears to be mountains with yellow sky about two-thirds across.
4. Click that image and it will give you a pop-up with the prefex of a URL.
5. In that box you simply cut and paste the URL of the image you would like to post.
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