Select the image to clip by selecting the image boundary.
At the Command prompt, Enter
n (New Boundary).
If prompted, enter
n (No) or
y (Yes) to delete the old boundary.
Enter
p (Polygonal) or
r (Rectangular), and then draw the boundary on the image.
If you are drawing a polygonal boundary, you are prompted to specify consecutive vertices. To finish drawing a polygon, press Enter or right-click anywhere in the drawing area.