you will have to upload them to a hosting site, tinypic, imageshack, photobucket, etc. Then you can do a coupling things.

1 just simply paste the url link into the your message, readers will have to copy and paste the link into their browser to see the pictures
2 put the link in the box below the message of a new post labled "optional link" and then name it. this will give readers the abililty to click the link to your picture. Drawback is you can only do one.
3. after you upload a picture to a site you will see the option for the url. Copy and paste into your message the one that says "HTML for websites/code" This will show the image in your post. If you have multiple images I suggest making an account at photobucket so you can manage your pictures easier. Its free to sign up.

hope that helps!