A wearable computing system may include a head-mounted display (HMD) with a display configured to display images viewable at a viewing location. When aligned with an HMD wearer's line of sight, the entire display area of the display may be within the HMD wearer's field of view. The area within which an HMD wearer's eye can move and still view the entire display area is termed an “eye box.” However, if the HMD slips up or down, the display area may become obscured, such that the wearer can no longer see the entire image. By scaling or subsetting an image area within the display area, the effective eye box dimensions may increase. Further, in response to movements of the HMD with respect to the wearer, the image area can be adjusted to reduce effects such as vibration and slippage.