I use IMGUR and the Admins gave me this easy method (Note: Not in BBCode mode as noted above.).
After the "Reply to this topic" box opens, place the cursor where you want the pic to appear.
Go to your imgur account and right click on the pic.
In the menu that opens left click on "Copy image".
Return to the post and right in the body where cursor is flashing
In the menu that opens left click on "Paste"
VOILA!