On the image resize drop-down menu choose "640x480 (for message boards)".
Click on browse.
Select the photie you want from the files on your computer - highlight it and click on "open".
Then click on "upload now" and wait for it to upload the image.
When it has uploaded a pop-up may appear asking you to register. Close this pop-up, you don't need to register.
You will see a small version of your photie. Go down to "links to share your image". Copy the one called "HTML code" and paste this into your post on the Blether Bar.
That's it!
While I've been typing this I've been going through the procedure with an example. Me graduating with that MSc! Let's see if it worked: