OK, it's fairly easy but there is a little trick to it.
Instead of using the normal reply box, up in the upper right-hand corner of the previous posting there is a Reply button. Click on that and it will take you to an advanced screen.
At the bottom left side of that reply box you'll see where it says "Click here to upload images and files!". Yup, click on that and another little screen will pop up. Click on "Browse" and find the shots in your 'puter. Once you've found all of the shots that you want us to see, hit "OK" and let it upload your shots. It will let you know when it's done then close the box then finish posting as you normally would.
This site won't accept videos, you can only link to those. Hopefully when they get the new servers online it will have that feature.