To post a photo. Click on the button with the photo with the disc in front of it (host an image). You'll see a box with the following... Upload your image
File url Resize image
At the bottom, you'll see a button saying "host it"
Choose your picture to host. Then you'll see the box with options to pick "Thumbnail, Image and Image URL". Click the link for thumbnail, and click copy. Then right click and choose Paste to enter the image on to your post.