When you are writing a post there is a rectangle shaped button that has upload picture on it. Click on this then go to browse. Select the picture you want to post and click send. Now the picture will come up in the window. Underneath the picture it says insert picture: standard and insert picture and insert another. If you only want to post one pic click on insert picture: standard. If you want to post more than one pic click on insert picture and insert another and repeat the process.
Once the picture is inserted it will come up as a URL address in your post. When you submit your post it will then come up as a proper picture.
Hope that hepls!!