Firstly you will need a image hosting account such as photobucket.com.
Upload your pictures to it and copy the direct link.
Once you have copied it, there is a button marked img in the toolbar above, click this and paste the link between the two img's in brackets. Your image will be displayed when you submit the post or preview it.
[img] [img]
.......^
paste link here.
The image will not be shown until you submit the post.
