Morning Aggers,
First thing to say is that the disappearance was nothing I did. We cannot get into each other's post and modify them, so I am as baffled as you are.
The problem I discovered was with the link address. It could be that it lead to a closed/private album, and Flickr for some reason has limited/restricted direct linking according to the site FAQ. When you made the photo public via the link in the photo board I was able to copy that new address and make a direct link, as we can see above. Flickr, TBH, looks to have gone all FB come Twitter... it's a bit of a mess.
You were asking about alternatives. I think the one you were after is Photobucket:
http://beta.photobucket.com/ I used to use it, but it got a bit pushy with its offers and stuff. My favourite is TinyPic:
http://tinypic.com It is a simple load up and link site without all the commercial bumpf.
The other part of your post is a bit of a mystery and you might need to speak with Kaz. I have to log in when I want to post because I kill cookies when my browser closes down. However, if I kill a tab to make space I stay logged in so that when I come back to VV I can post straight away. Maybe it is a mix of that type of thing that caused your problem? Under normal (logged out) situations the Photo board is private. Guests cannot even see that it exists.
If you need help just shout.