Selects a region/section of an image and keeps only the defined area. It’s similar to using scissors to cut away everything outside the area you want.
When you click Crop, the tool becomes two intersecting lines that you use to mark the area you want by forming a rectangle over the image.
Example: Click and hold the primary mouse button, then drag the lines diagonally until you enclose the area you want to keep. This is the same process used to crop a photo. (See the Region Capture tutorial for an example.)
This tool is also in the Edit group in the Edit tab.