Crop Image
This tool is used to clean up an Image at the extents of a polyline
boundary. First, select the boundary polyline(s). Everything in the
Image to the outside of this polyline is removed. Warning: this
command will update the Image seen on the screen as well as the
source Image.
Pulldown Menu Location: Raster > Crop Image
Keyboard Command: rascrop
Prerequisite: an Image and a closed polyline