How to Invert Colors in Paint for Windows 7
Inverting colors essentially creates a "negative" image of the photo, where light colors are dark and dark colors are light. Although digital cameras have all but eliminated film, you may still be familiar with negative slides, from which photos are created. Windows 7's Paint program offers the ability to invert colors into negative images, and further allows you to selectively choose portions of a photo to invert.
Open your photo in Paint.
Click "Select" from the "Image" group of the "Home" tab.
Click and drag your mouse to select a portion of the photo, if you only wish to invert part of it. To invert the entire photo, you do not need to perform this step.
Right-click the photo, or the selected portion, and choose "Invert Colors." The colors are automatically inverted.
Hold the "Ctrl" key and press "S" to save your work.