It is very easy to link to Flickr so that the image shows here.
Step 1: Under a Flickr image, there are several icons (see the attachment), click on the arrow one
Step 2: Select BBCcode (i.e., Bulletin Board Code)
Step 3. Select the desired size
Step 4. Flickr will already have the link highlighted, just copy it
Step 5. Paste it in the LuLa Reply field. You can even preview it before posting
That's it.
It takes more to explain it than to actually do it.