When you work in Photoshop, your files are given dimensions according to the default unit of measurement. For example, if the default unit of measurement for the program is set to inches, any time you display the rulers they will use inches.
Because web files display on computer monitors instead of the printed page, they use the unit of measurement for screens—the pixel. So, when customizing Photoshop for web design, you should use pixels instead of any other print-based method of measurement for all files.
To change the default unit of measurement in Photoshop, choose Edit I Preferences I Units & Rulers. Then, from the Rulers menu, select Pixels (as shown in the following illustration). Note that you can also get to the Rulers menu by double-clicking the rulers surrounding any of your images. If the rulers aren't visible around your image, you can make them appear by choosing View I Rulers or pressing CTRL-R (Windows) or CMD-R (Mac).
Was this article helpful?