Go advanced. Manage attachments. Paste the url of the image into the field that asks for the image url. Upload. Close the pop up. Find the paperclip icon in the header of the edit box. Insert image link by clicking the one you want in the drop down.
Or to hot link, go to the picture online, right click, pick 'copy image location'... Then back in the reply box, click the image tag button (pale yellow square) ... ctrl_v... make sure there is only one
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