If you’re developing a site from a Photoshop PSD file but find that things like font sizes, e.g. 12 pt, don’t look the same size in your browser where you’ve set the CSS font size to 12 pt, then you probably need to adjust your PSD file’s resolution.
To determine the resolution of your screen, you can go to
http://www.infobyip.com/detectmonitordpi.php
Mine says 96 dpi. Then, in Photoshop, go to Image > Image Size and set the resolution to 96 and uncheck the “resample” checkbox.
