Things to check:

If you are unable to load the New and Improved Uploader, check the minimum browser requirements.

If it loads, but does not get photos, try closing your browser and restarting it. Verify the folder you are selecting has photos inside and that you are dropping the files into the panel that says "drag and drop your photos here".

If you are still unable to use the New and Improved Uploader, you can also use the Original Uploader to select photos one by one. Click the Original Uploader tab and use the Browse buttons to add pictures.