Click 
.
Position the cursor over the image and click and drag outward from the area you are emphasizing. The arrow is displayed on the image with the arrow positioned at the point you clicked first. Nodes mark each end.
Enhancing Images > Using the Tool Box Toolbar > Using the Drawing Tools
Use the Pointer tool to draw an arrow to emphasize an area of interest in an image.
To draw an arrow:
Click .
Position the cursor over the image and click and drag outward from the area you are emphasizing. The arrow is displayed on the image with the arrow positioned at the point you clicked first. Nodes mark each end.
To change the properties of the arrow, use the Annotations Properties toolbar. See Changing Annotation Properties for more information.