SImply click all sizes for the image you want to share, while on flickr, and than decide what size you want to share. Once that is decided scroll to the very bottom and there should be two boxes. Copy what is in the second smaller box.
Than switch over to this site, click the lanscape image icon (14 from the left), and a pentax forum box should pop up. Paste the link you copied from flickr there and Bam done