Problems uploading photos in Safari with Mavericks

I have a 13" 2013 MacBook Air that I updated last night.

The update included Mavericks and a new version of Safari.

Now, I have major problems when trying to upload photos. Updating my Twitter avatar, for example. For whatever reason, the finder box opens, nothing shows and then it gets stuck and Finder crashes.

Each time this happens I have to force quit on Safari and start over. It always works the second time (if Finder isn't still stuck). It seems like I need a fresh browser instance for it to even work.

Anyone else experience the same or is it limited to me?