How to invert color
Open the image in Paint.net the command "Open" in menu "File" or Ctrl+O. In the web chart for selection of colors when creating images using a color wheel consisting of primary and complementary colors and transitions between them.
The basic colors are red, yellow and blue, extra purple, orange and green. Additional colors are obtained by mixing the primary. Colors lying opposite each other on the color wheel are called opposite. The opposite of blue is yellow, red blue, purple green etc.
To invert the color of the entire image, the menu "Correction" and click "Invert colors". If you want to change the color of a specific fragment, it first must select it. For allocation of an object of complex shape you can use the tools "Magic wand" and "Lasso" in the toolbar. The command "Invert colors" will be applied only to selected areas of the picture.
How to change the color
On the toolbar, click on the "Replace color". While holding the Ctrl key click on the section of the image whose color you want to replace - in the palette it will be the main. On the color wheel select a new color for designated area. After this, the main will be the replacement color.
In the properties panel, adjust the tool diameter and sensitivity. The lower the sensitivity, the selective valid "Replacement color". At 100% sensitivity, it works like a brush. Paint scheduled area, if necessary, changing the sensitivity and the tool diameter.