Hi Sue,
First open a post and at the bottom you will see additional options. Click on additional options and then browse until you find your image on your computer. Open your image and it will appear on the attachment. Post and your image should appear on Rootschat. That is the first step. The image can only be a certain size.
Second when you have the image on a posting, right click on the image and you will get properties including the address of the image.
Right click on the address and copy for pasting. Open your profile and paste the address into" I have my own image".
Hopefully it will appear.
Good luck but I suspect that you will require a few attempts.
Geoff