in reply to
using GD inside CGI...
You can create two diferent cgi (or the same cgi called with diferent parameters), one to return the HTML, and the other to return the image.
Or you can have the cgi that return the html process and save the image to disk, and then in the HTML put the URL to that image. This is what I would do, because this way I already know that the image was correctly processed when I send the HTML to the client.
The last alternative (that I never tried) is to put the image in base64 (I think) in the HTML. If you prefer this on (I hope not), you can read about it in http://www.unixreview.com/documents/s=8217/ur0305h/.