Undo or redo an edit in Windows Paint
If you make a mistake editing a picture, you can undo the mistake as long as you do not hit save. Once you hit save, you will not be able to undo the mistake. If you haven't hit save and want to undo a mistake on a picture you are working on, just click on Undo
If you undid a step and then realized you should have kept that step, you can click on redo, you can redo the step as long as you do not hit save. Once you hit save, you will not be able to redo the step. If you haven't hit save and want to redo the step on the picture you are working on, just click on redo