You need to upload them from your camera to an online account like photobucket.com.
Join them, it's free, and when it opens your album there will be buttons that say choose file, click that and then it will bring you to your finder. Find the picture you want to post and then click choose, when you are done adding the pics hit upload. This will take a few minutes.
After everything is loaded to your online album, click the picture to edit it. you want to resize the picture for the message board size. Then the last step is clicking the IMG code, when you click it a tag will say "copied" then paste it in a thread. I'm not sure if you need a minimum number of posts on the DIS before you can post pics though. You could ask about that on the welcome forum.
Sorry it took so long to reply but with the kids running around I can't concentrate on the steps you have to follow.