Hi Reg,
I usually use Google Chrome, but it is easier to post using Internet Explorer.
1. Go to your image on Flickr and right click on it.
2. Choose Medium as the size.
3. A new page will come on, right click again.
4. Scroll down to "Properties" and select that.
5. On Properties you will see a link, copy and that paste that link to the forum. Remember to use the 2 Img codes:
For example I have used one of my photos as an example: