Doug,
I have found that all I need to do is bring the image up that you want to show,find the line that says "img" left click on that. It should highlight for a second and say "copied".
Now go to Tradgang and the thread you want,right click and it will show you some choices. Click on paste and it should print out a bunch of numbers and letters across the top. Type in any remarks you need to and then hit "Add Reply" at bottom of box.
Picture should appear shortly after.
Craig