1. A method comprising: displaying content on a transparent or semi-transparent display of a head-mountable device (HMD), wherein the displayed content is perceived by a wearer of the HMD as being superimposed over a real-world field-of-view seen through the transparent or semi-transparent display; making, by the HMD, a determination that a trigger event occurred; responsive to making the determination that the trigger event occurred, both: (i) generating, by the HMD, a first image of the displayed content, and (ii) causing, by the HMD, a camera to capture a second image of the real-world field-of-view associated with the HMD; and generating, by the HMD, a composite image that combines the generated first image, the captured second image, and an effect image by overlaying the generated first image on the effect image and overlaying the effect image on the captured second image, wherein the effect image improves the accuracy of the generated composite image's representation of the wearer's view, and wherein the effect image is neither displayed on the display of the HMD nor part of the real-world field-of-view associated with the HMD.