These workflows are coming along nicely – pretty excited to try them out soon! :)

For the multiple upload workflow, I prefer option 1 (creating a default title + sequential number for each image, and allowing the user to edit the description/add categories after upload). This generally follows the UI pattern on other sites that allow batch uploading (I'm thinking specifically of Facebook and our very own desktop Upload Wizard, but there are probably other examples), and given the high user/contribution quality we're seeing on the app, I'm not particularly worried about people dumping a bunch of files and then not describing/categorizing them. 

I'm still wondering whether there's any real merit in making the user enter a custom title and a description, though. There's more thinking and room for error involved on the user's part (if they pick a filename that's taken, they won't be able to upload), and in practice most titles and descriptions are identical. I know this is a legacy workflow from desktop uploading, but I still think we should shake things up a bit and push for less work on the user's part/more streamlined metadata :)