+1 I also don't like what Flickr has done to the interface. I'm also having trouble loading, hanging, scrolling. And it's not easy to navigate anymore. They at least had the option to disable this photo fitting and retrieval 'feature'. It's annoying. Maybe we need to link this thread to their customer service address.

I just renewed my pro account before they switched too. GRRR!
I have too many photos on Flickr, hope they will 'fix' these upgrades.

As for uploading, I've been using their Flickr Uploadr app for Windows, since the old interface. It's a lot more stable than uploading via their webpage. It uploaded my latest pics fine to this new Flickr.