Once you save the chart image to a file on your computer, you can go to http://www.imageshack.com and upload it. Once its uploaded, copy the FULL IMAGE link that they give you. For example
It's easy, gloe. Once you save the chart to a file on your computer, you use imageshack to host it on the web, then copy the URL in imageshack and post it in your msg on ihub by typing "[ chart ]" without the spaces or quotes, then paste the URL (removing the http://) and then type "[ /chart ]" without the spaces and quotes, and the chart will appear in your msg.