Carole,
In order to post a picture, just find one on the Internet somewhere, get the properties of it (assuming you're using Windows), and copy the URL. The URL will end in the extension of the picture, e.g. jpg, gif.
Then when you reply, click on the Image button, which will pop up a window showing "http://" hilited. Just paste the picture's URL and hit OK. To see the result, use the Preview Post option.
If you need practice, try pasting a picture in the "How To's" section.
I'm sure this is in the FAQ's, but it's faster to explain it here than to search for it.
Hope this helps.
