You can either Upload your pics here to the site, as attachments, But I think You have to be careful about the size..I do it a different way..

I upload my pics to either Photobucket.com or Webshots... they give you the HTML codes and easy to choose your size too..

Then, using Photobucket as the example --Select the HTML code for Your pic and Copy it..Then come Here, in your composing/reply window --Click the tab at the bottom of this window, that says "Html"...And paste the code --jump back over by clicking the "design" tab and You will See Your Pic.

Ok, If Thats not too clear..Let Me know, I will try to explain better..