First, thanks! Also, it needs to be largely viewed and shared widely on the web. This could mean on Twitter, but does not have to be on Twitter. But a combination of, for example, Reddit and Twitter. 

That's weird. We're unable to reproduce that problem though. If you can give step-by-step instructions as to how you're getting that error, we can try to be of more help. 

How so? When you are clicking 'next'? 

You cannot drag and drop folders, but you can highlight all 50+ images and drag and drop them at once. 

Thanks for the suggestion. We will add it to the to-do list. 

Thanks for the suggestion; I'll add it to the list!

There are more thumbnail options with pro accounts.