I am new to greenshot, I edit ed an image saved it and went back to change text and remove arrows, and cannot edit the save annotations, am I doing something incorrectly?
You are doing everything right. Currently, Greenshot is designed to add annotations, highlighting etc. to your screenshots once, and then export it to wherever you need it.
However, we are aware that there sometimes is need to re-edit those later, and took first steps in this direction. We will most probably add this functionality with one of the next releases.
Thanks for your feedback and best regards,