Slobodan Blagojevic: The real question is why would I want to post larger? To make it more attractive for thieves to still it and/or print it?
Mike Deerkoski, Thanks for your responses. I am also concerned with the exactly the problem described by Stig. However, i do not exactly understand why it would be difficult for flickr to allow a user manually regenerate missing sizes. I can see doing it automatically for all photos is a lot of load but it is much much less load to allow a user to do it. Mostly pro users are interested to have these sizes and even not all of them. There should be no problem to allow user to generate missing sizes for their photos. I just paid today to flickr for 2 years pro account and waiting for this feature. Thanks.