Samantha's not currently actively working on social tools. You can access the main PictureGame special page at Special:PictureGameHome. Specifically you'll want to be on the form for creating a new picture game; the URL will be something like http://localhost/devwiki/index.php?title=Special:PictureGameHome&picGameAction=startCreate
Ensure that you're logged in as a user who can upload files (and that file uploads *are* enabled in the first place!) and that the copy-by-upload feature ($wgAllowCopyUploads = true;) is enabled in your wiki's LocalSettings.php and that a user group that you're a member of has the upload_by_url user right.
Once these prerequisites are met and you're on the aforementioned special page, the UI glitch that this ticket describes should be painfully obvious.
I look forward to reviewing your patch!