Selecting geometric areas such as circles, ovals, and rectangles is a common Photoshop task. Reasons for selecting geometric areas include lightening an area to place text on it, deleting a section of the image, or preparing to crop the image.
Open the File
Choose File, Open to open the desired file.
Select the Marquee Tool
Select the Rectangular Marquee tool to draw a rectangular selection; select the Elliptical Marquee tool to draw an oval selection. (Other tools offer you the option of selecting a vertical or horizontal row of a single pixel.) To select any tool not currently visible in the toolbox, click and hold the current marquee tool and drag to the desired tool in the pop-out menu that appears. Note that the selected tool now appears on the toolbox button and in the Options bar at the top of the screen.
Drag the Selection
Move the cursor onto the image and click and drag to draw the selection. If the selection is not where you want it, click once outside the selection to deselect the area, and drag to redraw the selection.
Move the Selection as Needed
After you create the selection, you can move the selection area (the ellipse or the rectangle, for example) to another area in the image. With the Marquee tool still selected, click inside the active selection and drag to move its location.
Deselect as Necessary
If you need to deselect the area and start over, choose Select, Deselect to deactivate the current selection. You also can deactivate a selection by clicking outside the selected area or by pressing +D (Mac users) or Ctrl+D (Windows users) when using any of the marquee tools.
Selecting a Specific Size
To make a selection of a specific size, choose Fixed Size from the Style menu in the Options bar and type the dimensions, in pixels, in the Height and Width fields. Click in the image to create a selection matching the dimensions you entered.
Selecting a Size Ratio
To select a perfect circle or square, press and hold the Shift key as you drag the selection. To constrain any other size ratio (that is, to drag a selection area that preserves a height/width ratio), select Constrained Aspect Ratio from the Style menu in the Options bar and type values for the desired width-to-height ratio.
Drawing from the Center Out
To draw a selection from the center out instead of drawing it from a corner down, hold the Option key (Mac users) or the Alt key (Windows users) as you drag.