Guides and the grid help in positioning images or elements precisely.
Guides appear as nonprinting lines that float over the image that can be moved or removed. You can also lock them so that you don’t move them by accident.
Smart Guides help you align shapes, slices, and selections. They appear automatically when you create a shape, selection, or slide. You can hide Smart Guides if necessary.
The grid is useful for laying out elements symmetrically. The grid appears by default as nonprinting lines but can also be displayed as dots.
Guides and grids behave in similar ways:
Selections, selection borders, and tools snap to a guide or the grid when dragged within 8 screen (not image) pixels. Guides also snap to the grid when moved. You can turn this feature on and off.
Guide spacing, along with guide and grid visibility and snapping, is specific to an image.
Grid spacing, along with guide style, is the same for all images. The guide color is now specific to images.
Choose View > Show > Grid.
Choose View > Show > Guides.
Choose View > Show > Smart Guides.
Choose View > Extras. This command also shows or hides layer edges, selection edges, target paths, and slices.
If the rulers are not visible, choose View > Rulers.
For the most accurate readings, view the image at 100% magnification or use the Info panel.
In the View > Guides > New Guide submenu, select Horizontal or Vertical orientation in the dialog box, enter a position and color, and click OK.
Drag from the horizontal ruler to create a horizontal guide.
Hold down Alt (Windows) or Option (macOS) and drag from the vertical ruler to create a horizontal guide.
Drag from the vertical ruler to create a vertical guide.
Hold down Alt (Windows) or Option (macOS) and drag from the horizontal ruler to create a vertical guide.
Hold down Shift and drag from the horizontal or vertical ruler to create a guide that snaps to the ruler ticks. The pointer changes to a double-headed arrow when you drag a guide.
(Optional) If you want to lock all guides, choose View > Guides > Lock Guides submenu.
Select the Move tool , or hold down Ctrl (Windows) or Command (macOS) to activate the Move tool and select or move multiple guides.
Drag the guide to move it.
Change the guide from horizontal to vertical, or vice versa, by holding down Alt (Windows) or Option (macOS) as you click or drag the guide.
Align the guide with the ruler ticks by holding down Shift as you drag the guide. The guide snaps to the grid if the grid is visible and View > Snap To > Grid is selected.
You can now select guides (single or multiple) to edit them. Click on the guide to select, and the double-headed arrow will appear.
You can also add a specific location to place your guide. Once placed on the canvas, this can be moved or adjusted for color and orientation.
(Windows) Choose Edit > Preferences > Guides, Grid, & Slices.
(macOS) Choose Photoshop > Preferences > Guides, Grid, & Slices.
For Color, choose a color for the guides, the grid, or both. If you choose Custom, click the color box, choose a color, and click OK.
For Style, choose a display option for guides or the grid, or both.
For Gridline Every, enter a value for the grid spacing. For Subdivisions, enter a value by which to subdivide the grid.
If desired, change the units for this option. The Percent option creates a grid that divides the image into even sections. For example, choosing 25 for the Percent option creates an evenly divided 4‑by‑4 grid.
The latest enhancements to the Guides feature let you customize the functionality of your guides at the document level to improve your creative work.
This includes the ability to colorize and edit guides via new keyboard shortcuts and a new context menu.
You can also delete guides with the Delete key and multi-select guides to edit and move them.
Get the latest version of Photoshop to try out this cool enhancement!
New dialog boxes (as shown below) include the option to colorize individual or multi-selected guides, making identification and visual isolation of guides much easier.
Select the Move tool and use the mouse pointer to point to the guide. Then use the keyboard shortcuts option + shift double click on your Mac or Alt + Shift double click on your Windows system to open the Edit selected guides dialog box.
To delete guides, go to View > Guides and select Clear selected guides. You can also select guides and hit right-click to delete them from the context-sensitive menu that appears.
Alternatively, you can multi-select guides by clicking option + shift (Mac) or Alt + Shift (Win) and hitting the Delete key.
Smart Guides come in handy in several scenarios, such as the following: