WordPress.org

Is Thumbnail Viewer a photo manager?

Absolutely not. It simply displays large versions of smaller images (thumbnails) in an unobtrusive yet stylish overlay.

Can images in the form of WordPress attachments be displayed?

Nope, see previous answer.

Where can I find support?

Visit http://www.longren.org/ and get in touch with me (Tyler) there.

Why can't I see the quicktag when I'm writing a new post or editing an existing post?

If you're using the Visual Editor, click on the Code tab, you'll see the quicktag there.