Gimp digital image processing useful program to edit the images at a professional level is Gimp.
Gimp GNU is a free program you can download it on https://www.gimp.org/. With this program you will have an array of sophisticated tools such as cones can do a great job. Obviously even third-party plug-ins are available to use many custom options.
Installation is easy and fast, below the standar screen of Gimp digital image processing.
In addition to full screen there are three boxes, or toolbox. Naturally one main is the toolbox containing the main drawing tools a toolbox containing the brushes and options.
It can happen accidentally to close these three toolbax. Obviously in this case when the program is restarted the settings remain stored and the toolbox does not reappear. Clearly to reset to default window, will be necessary from the main screen go to: edit (second item from left ) -> preferences (fifth from voice edit) click, go to window management (second to last item in the list), click, and select reset to default values saved window position. In this way you will reset the default toolbox.