First of all the image has to been on the net. (No HDD) Photobucket is a good place to put up images... HERE is the link.

[img src="www.whatever.com/image_you_want.jpg"]
but you'll need to replace the [ ] to < >

Put

&ltimg src="URL OF PIC HERE"&gt

Copy and paste this, just change the url:

&ltimg src="www.yourpicaddress.com"&gt