I accidentally clicked the "report a bug" link in Gmail today and was surprised to be taken to a beta for Google Feedback, which is apparently a newish plugin for Firefix, IE and Chrome that allows you to send an annotated and (manually) sanitized screenshot along with your feedback:

"Sending your feedback is easy using Google Feedback for Firefox. Just click the feedback link, mark up the page, enter a description, and send your feedback straight to Google."

"Google Feedback is currently in limited beta, so it will only work if you’ve been invited to help with this initial test. Please let us know if you’re interested in trying it out."

http://www.google.com/tools/feedback/intl/en/firefox.html
http://www.google.com/tools/feedback/intl/en/learnmore.html

Yes, this tool is limited to trusted testers for the moment.

it was launched in early april