Your question: How do I add a gradient to an image in Illustrator?

Click the Gradient tool and then click the object on the canvas. The Gradient Type buttons are displayed in the Control panel or Properties panel. With the object selected, click Linear Gradient to apply the Linear gradient on the object. In the Gradient panel, click Linear Gradient.

THIS IS FUN:  Your question: How do I remove the white background from an image in Photoshop?