For flickr, you just click on the "share" down arrow button, highlight & right-click to copy the BBCode and select the size (I use medium 640 x 427) and then post the code directly in the quick reply box.
http://farm7.staticflickr.com/6054/6...aacc1a41_z.jpg
Lucky Charm by Denise Trocio, on Flickr
I do wish there was a preview button though before hitting the "Post Quick Reply".
Denise