Work with Levels in Gimp (tip)
To quickly adjust highlights and tone of an image we can use Levels tool.
Open an image in Gimp and then to access level tools we will click Tools -> Color Tools -> Level.
Then if we want to work with level curves we will click on Edit these Settings as Curves button.
When processing an image the idea is to obtain an S curve that looks good, without blowing out image with too much white and without black/too dark areas.
Note: The same tool can be accessed from Colors -> Levels submenu.
Gimp level tool is very useful for image processing.