On your flickr page - open the picture you want - and choose which size you want to post
Beneath the photo there is text for 1. and 2.
At 2. it says " 2. Grab The Photo's URL'
highlight the entire string in the box ( it will turn blue)
use the CTRL, and C keys
( Ctrl-C is copy, Ctrl-V is paste)
Come back here, click the 'Insert Image' icon - it is the yellow one with the mountains - it will say 'Insert Image' when you put your mouse over it.
When the prompt comes up use the Ctrl-V keys to paste the text you just
This photo link looks like this(without the * at either end: