Any suggestions for a solution to a new problem on Flickr? How can I delete a photo?

I have been using the app for several years and have never had a problem until how. When I write to the Help people, I get incomprehensible gibberish from Yahoo!. The forums are equally exoteric and user-unfriendly. As a much smaller concern, I can no longer add tags either. It used to be straightforward. Mac OS 10.8.2, Safari and Firefox.