The marquee tools let you select rectangles, ellipses, and 1‑pixel rows and columns.
Makes a rectangular selection (or a square, when used with the Shift key).
Makes an elliptical selection (or a circle, when used with the Shift key).
Single Row or Single Column Marquee
Defines the border as a 1‑pixel‑wide row or column.
Specify one of the selection options in the options bar.
A. New B. Add To C. Subtract From D. Intersect With
For the Rectangular Marquee tool or the Elliptical Marquee tool, choose a style in the options bar:
Determines marquee proportions by dragging.
Sets a height-to-width ratio. Enter values (decimal values are valid) for the aspect ratio. For example, to draw a marquee twice as wide as it is high, enter 2 for the width and 1 for the height.
Specifies set values for the marquee’s height and width. Enter pixel values in whole numbers.
In addition to pixels (px) you can also use specific units such as inches (in) or centimeters (cm) in height and width values.
To reposition a rectangular or elliptical marquee, first drag to create the selection border, keeping the mouse button depressed. Then hold down the spacebar and continue to drag. Release the spacebar, but keep the mouse button depressed, if you need to continue adjusting the selection border.