by Julieanne Kost
In dialog boxes referencing width and height (New File, Image Size, Canvas Size, etc.) if you change units of measurement for one of the dimensions Photoshop will automatically match the units for the other dimensions (i.e. if you select pixels as the units for width, Photoshop automatically changes the height to pixels). If you need to enter in two different units of measurement, holding down the shift key will override this feature to allow different units for each value.