The photo in my previous post was taken with my shiny N95. The N95 is capable of uploading photos to Flickr (and other services), but when I tried to configure it it kept rejecting my credentials. It turns out you need to use a special one (not your normal Flickr/Yahoo! ones) which you can get by visiting their N95 configuration page.
Once I set my credentials accordingly, it all worked fine. I wonder if I’ll start using Flickr more now…