Try scrolling past the Image Shack screen in the Tutorial-Walkthrough - How to Post a Picture In Your Post. The Image Shack screen is just there as an example of a place to get images, and only to show how/where to find the link code for photos so that you can copy and paste the links as an example. If you scroll further down in the Tutorial, it will shows a more recognizable screen for posting on PC that has the the icon (yellow box with the mountain peaks and sun/moon in it) to use to upload images when posting in threads and PM's. Perhaps this will help. Did this work?

You are welcome to send me a PM to try it out posting an image. Good luck.