We all seem to have the problem where photos from Flickr "disappear" on posts. I may have found the solution...

When you copy the link from Flickr, the last bit of looks like this: / > < / a > (but without the spaces which I had to put in so you can see the text).

I took out the first / so it now looks like this: > < / a > and (fingers crossed), it works and the photos show up properly. Hope that helps somebody!