I panicked, too, when I was hurrying to add pics to a listing, and *bam* got a completely unfamiliar uploading window. It was upsetting - sellers are often working at full speed trying to get stuff done.
I did figure it out after a little (stressful) fiddling.
You guys at Auctiva usually provide really great, personalized service, in my experience.
However, when you are springing a big change like this on busy, multi-taking users, you really should give a heads-up. A simple little tutorial would have gone a long way to ease the transition, too.
I hope Auctiva will carefully consider making these transitions smoother in the future.
My platform is Mac/Chrome, and everything is working fine now. I even think I'll like it once I get over the initial trauma. ha.