Seems a good tool to take screeshots, upload it automatically, and remember automatically from which site/URL it is from. Lack of flexibility, if I want to use it to tag images, and not to report bugs. No free plans at all, but there's a trial of several days. I won't use this paid service, as I have already Lightshot.

the screenshot can not be saved to disk

The tool might be fine for those who accept the trade-off. For me a screenshot tool that needs a server and premium account is rather useless - sorry, not sorry. No offline, NO-GO

Amazing tool, but it requires a login and premium account to save or anything. I just want a screenshot without jumping through 5 different hoops. I don't even see why businesses would pay either

I've been a heavy user of Marker on Chrome for a while, but I'm super happy that it's now available on Firefox, as it is my daily browser.
The fact that Marker lets you capture, annotate and then share your screenshots exactly the way you want makes it a must-have if you're involved in the process of creating or testing any type of web site or application.

Absolutelty AMAZING! I use the Marker.io Firefox extension to debug my website across all browsers. Whenever I find a bug on my website, I grab a screenshot with the extension, add annotation and create an issue in JIRA, a card in Trello or a message in Slack if our team still need to discuss the bug.

Highly recommended!