Certain embodiments involve calculating a vanishing point location of an image to realistically blend multiple images. For example, a method for modifying image content based on a vanishing point location computed for a background image includes receiving the background image and classifying a set of planes in the background image. The method also includes identifying, using plane boundaries, a first set of line segments that define first convergence points. Additionally, the method includes identifying a second set of line segments that are positioned within individual planes and that define second convergence points. Further, the method includes grouping the first convergence points and the second convergence points into a cluster and computing the vanishing point location from an average of point locations in the cluster. Furthermore, the method includes manipulating a feature image overlaid on the background image to generate a blended image based on the vanishing point location.