Digital images are different from paper images. Physical paper images can be cut into any shape, while digital images can only be rectangular. Usually, digital images with arbitrary shapes are only filled with white at the edges, but their essence is still rectangular.

As shown in the figure below, to make it oval, the method is:

1. Select the elliptical marquee tool.

2. Draw an elliptical selection, as shown below:

3, choose-reverse phase.

4. Edit-Fill-White Fill, as shown below: