Easily how to trim a part in an image - Photoshop 7
Photoshop offers effective tools to select one or more parts of your image, to copy or delete, for example.
We'll show you how to use the magnetic lasso (shortcut L). Consider a face to a photo montage example.
Click L to select the lasso. Then click the first selection point you want, then drag the mouse along the desired path. The software selects only certain points defining the outline, but you can even define some contour points by clicking at the desired location. Return to the starting point and click to finish the loop.
Copy the selection obtained and paste it either on a new layer, or a new image.
Tip: You can invert the selection using the menu Select / Invert (shortcut Shift + Ctrl + I).