Posting pictures is really easy once you get the hang of it. The first thing you need to do is to upload them to an online hosting site...most people use Photobucket:http://photobucket.com/
It very user-friendly, and best of all, free!
Once you register there, you can start uploading pictures to your albums there. When you upload a picture, make sure it is no bigger than 640 pixels wide...there is an uploading option on Photobucket that will upload them to that size, or whichever size you choose.
When you upload a picture, you will see it in your album. Below each picture are a set of codes. To make a picture appear within the body of your post, you right click and copy in the code that has the tags that look like this: [IMG]. When you submit your post, the picture will be there.