Would you give me a feedback on this image commenting tool MVP?

Hi everybody, my name's Matteo and I am an Italian designer working with some friends on Comment , a tool for fast and real time image commenting that I felt the need to create in order to give feedbacks during the creative process. Check the prototype here! The feeling is that sometimes tools as Invision or Zeplin (with downloads, signups etc) are just too much when the only goal is to share a fast feedback with a colleague. And, I have to say it, I hate Apple's editing preview mode :) The idea is to have a webapp with no logins signups etc where you can drag and start commenting, copy a unique link and share it on slack etc. Just trying to reduce the number of steps to do that so that the process could really be simplified. Since I am the only one using it for now :) I am asking for an honest feedback to you.. do you think it could be useful? What would you change or integrate? Thanks in advance for your feedbacks!