Final answer:
To change a picture's brightness and contrast in Word, select the image, go to Picture Tools > Format, and choose the Corrections option to use presets or manually adjust with sliders.
Step-by-step explanation:
To change the brightness and contrast of a picture in Word, you should select the image and then click on the Picture Tools that appears on the ribbon. Once in the Picture Tools section, click on the Format tab. You will see options for adjusting the appearance of your picture. To specifically adjust brightness and contrast, look for the Corrections option within this tab. When you click on Corrections, a dropdown menu will appear with preset options for both brightness and contrast. If you want to set a specific value for brightness or contrast, click on the option at the bottom of this menu called Picture Corrections Options, and then you can use sliders to adjust brightness and contrast to the desired levels.