Crop a picture to a circle shape

If you want to crop a picture to a circle shape seems only the oval shape is available.
You can adjust the format though.

Insert your picture and crop using the Crop button in the Size group on the Format tab.

After cropping click the dialog starter button in the bottom right corner of the Size group.

Click the picture button and the crop option.

Under Crop position, enter the same size next to width and height.