You want to add that link that you copied to the window that opens when you click this icon on your tool post tool bar.
Click it, a window will appear, remove the existing http:// that appears and paste your URL from Photobucket.
Now as for your picture....I have no idea....it looks like that black blob on the island of LOST.....ever watch it?
Ps, click edit on Photobucket and you can shrink the picture to fit on the threads. It should be the 600X400 size or something like that. Don't do it now cause it'll change the URL address and this pic won't show, you'd have to reedit it here.
. Which link I copy?
It's the second one down in the list of 4.....