David:
You have to have your pictures hosted in an account on a suitable site. I use photobucket.com, but there are others. It is relatively easy to get photos off your computer on to such a site - instructions are simple to follow and you can set it to save in a suitable size - 640x480 pixels at medium resolution gives a file size which CGT can accomodate. The site will then give you "tags" for each of your pictures and you copy and paste the tags into your post - CGT uses the "img" tag. And when you go back to your post - lo and behold, there is the picture - it also means that you can intersperse text and put a caption on each pic.
Phil