To include an image in your post, it must be on the web somewhere. This may be a CS garage or anywhere else where the image has a complete address, ie.
Note that this must be the image itself, not the page that the image is on. Places like MSN Groups etc. give you a bigger address and these generally don't work. When you have this, put it in between [img] and [/img] like so:
You'll notice that there is also a link in your CS garage called 'copy image BBcode' which does this for you. You then ctrl-v or right-click and Paste this in to your post.
Keep images sensibly sized - under 750 pixels wide otherwise the page will be distorted by it. Smaller images also download quicker.
[Edited on 04-04-2005 by Ian]