Hydro beat me to it
but here's what I typed up:
To post pictures
Click the "Post Reply" button (at left under the latest post). It will take you to a reply page.
On the reply page, under the text field, find "Click here to upload images and files!".
A small window will open saying "Select a file to upload:". Click one of the "Choose File" buttons and navigate to your image file.
Highlight the file name and click "Open". It should now be listed in the upload window. Still in te small window scroll down just a little and press the "OK" button.