Image annotations that remain changeable I want to edit images with annotations (text, arrows, ...). Preview does offer a nice set of tools but after saving they get embedded in the image and are not clickable/modifiable anymore. Using Time Machine to reset changes is much too cumbersome.

Do you know of any similar tools where i can easily alter annotations after saving (like Skim for PDFs).
Skitch



Skitch is a very useful app for making annotations on images, and whilst by default it saves the files using the format that they are imported as, it can save it as a Skitch PNG which keeps the ability to modify the annotations, or the files can be kept inside its own library.