Are you setting any access limits - like uploading the full image and then not allowing any one but friends/contacts to access fullsized images (it might even be a default setting).
Not that I can see. All my Flickr photos are public to view in all sizes, the only limitations being that only other Flickr users can comment, and only contacts can make notes. Pretty much the standard setup from what I can see.
hmm try just giving a link to your profile - lets see I can see the images on there
edit got there - and I can see the images. Hmm you checked that the linkback addresss is correct (its about all I can think that might be wrong)