Lasso: used to make free hand selections. It can’t be used for large area selections as it is required to hold down mouse key continuously until the selection was completed. (KBS: L). Generally used to modify the selections.

Using Lasso Tool:

• click to start selection on the image
• Hold mouse button and move along the edges of required selection
• Release mouse button to finish
• Hold Alt to change to Polygonal Lasso anytime

Polygon Lasso (KBS: Shift+L): used to make polygon shape selections.

Using Polygonal Lasso:

• Click in the image to set the starting point
• Continue clicking along the edges of your desired selection
• Hold Alt if you want free hand selection somewhere
• Use Del/Backspace to remove previous line segments
• Connect the starting and end points to finish selection. (or) Double click or Ctrl+click to finish

Magnetic Lasso (KBS: Shift+L): it traces and creates the selection points automatically while you are moving the mouse pointer around the part to be selected.

Using Magnetic Lasso:

• Click in the image to set the starting point
• Move pointer along the edges of your desired selection
• Hold Alt if you want free hand selection somewhere
• Use Del/Backspace to remove previous line segments
• If the selected point is wrong, you can manually click
• Connect the starting and end points to finish selection. (or) Double click or Ctrl+click to finish

Options of Magnetic Lasso:

• Width: specify the area from which point to be selected. Set caps lock on to change between actual/precision mode. Use ] or [ keys to increase/decrease lasso width
• Edge Contrast: values from 1% to 100%. Set higher value if edges of selection are very clear from background. Set lower value to select low contrast edges
• Frequency: values from 0 to 100. Higher the value picks the points quickly.
• Pen pressure: option useful only when working with Tab